Initial commit: release hytlass-0.1.0

googletest/googlemock/test/gmock-matchers-comparisons_test.cc

+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file tests some commonly used argument matchers.
+
+#include <functional>
+#include <memory>
+#include <optional>
+#include <string>
+#include <tuple>
+#include <vector>
+
+#include "gmock/gmock.h"
+#include "test/gmock-matchers_test.h"
+#include "gtest/gtest.h"
+
+// Silence warning C4244: 'initializing': conversion from 'int' to 'short',
+// possible loss of data and C4100, unreferenced local parameter
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4244 4100)
+
+namespace testing {
+namespace gmock_matchers_test {
+namespace {
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(MonotonicMatcherTest);
+
+TEST_P(MonotonicMatcherTestP, IsPrintable) {
+  stringstream ss;
+  ss << GreaterThan(5);
+  EXPECT_EQ("is > 5", ss.str());
+}
+
+TEST(MatchResultListenerTest, StreamingWorks) {
+  StringMatchResultListener listener;
+  listener << "hi" << 5;
+  EXPECT_EQ("hi5", listener.str());
+
+  listener.Clear();
+  EXPECT_EQ("", listener.str());
+
+  listener << 42;
+  EXPECT_EQ("42", listener.str());
+
+  // Streaming shouldn't crash when the underlying ostream is NULL.
+  DummyMatchResultListener dummy;
+  dummy << "hi" << 5;
+}
+
+TEST(MatchResultListenerTest, CanAccessUnderlyingStream) {
+  EXPECT_TRUE(DummyMatchResultListener().stream() == nullptr);
+  EXPECT_TRUE(StreamMatchResultListener(nullptr).stream() == nullptr);
+
+  EXPECT_EQ(&std::cout, StreamMatchResultListener(&std::cout).stream());
+}
+
+TEST(MatchResultListenerTest, IsInterestedWorks) {
+  EXPECT_TRUE(StringMatchResultListener().IsInterested());
+  EXPECT_TRUE(StreamMatchResultListener(&std::cout).IsInterested());
+
+  EXPECT_FALSE(DummyMatchResultListener().IsInterested());
+  EXPECT_FALSE(StreamMatchResultListener(nullptr).IsInterested());
+}
+
+// Makes sure that the MatcherInterface<T> interface doesn't
+// change.
+class EvenMatcherImpl : public MatcherInterface<int> {
+ public:
+  bool MatchAndExplain(int x,
+                       MatchResultListener* /* listener */) const override {
+    return x % 2 == 0;
+  }
+
+  void DescribeTo(ostream* os) const override { *os << "is an even number"; }
+
+  // We deliberately don't define DescribeNegationTo() and
+  // ExplainMatchResultTo() here, to make sure the definition of these
+  // two methods is optional.
+};
+
+// Makes sure that the MatcherInterface API doesn't change.
+TEST(MatcherInterfaceTest, CanBeImplementedUsingPublishedAPI) {
+  EvenMatcherImpl m;
+}
+
+// Tests implementing a monomorphic matcher using MatchAndExplain().
+
+class NewEvenMatcherImpl : public MatcherInterface<int> {
+ public:
+  bool MatchAndExplain(int x, MatchResultListener* listener) const override {
+    const bool match = x % 2 == 0;
+    // Verifies that we can stream to a listener directly.
+    *listener << "value % " << 2;
+    if (listener->stream() != nullptr) {
+      // Verifies that we can stream to a listener's underlying stream
+      // too.
+      *listener->stream() << " == " << (x % 2);
+    }
+    return match;
+  }
+
+  void DescribeTo(ostream* os) const override { *os << "is an even number"; }
+};
+
+TEST(MatcherInterfaceTest, CanBeImplementedUsingNewAPI) {
+  Matcher<int> m = MakeMatcher(new NewEvenMatcherImpl);
+  EXPECT_TRUE(m.Matches(2));
+  EXPECT_FALSE(m.Matches(3));
+  EXPECT_EQ("value % 2 == 0", Explain(m, 2));
+  EXPECT_EQ("value % 2 == 1", Explain(m, 3));
+}
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(MatcherTest);
+
+// Tests default-constructing a matcher.
+TEST(MatcherTest, CanBeDefaultConstructed) { Matcher<double> m; }
+
+// Tests that Matcher<T> can be constructed from a MatcherInterface<T>*.
+TEST(MatcherTest, CanBeConstructedFromMatcherInterface) {
+  const MatcherInterface<int>* impl = new EvenMatcherImpl;
+  Matcher<int> m(impl);
+  EXPECT_TRUE(m.Matches(4));
+  EXPECT_FALSE(m.Matches(5));
+}
+
+// Tests that value can be used in place of Eq(value).
+TEST(MatcherTest, CanBeImplicitlyConstructedFromValue) {
+  Matcher<int> m1 = 5;
+  EXPECT_TRUE(m1.Matches(5));
+  EXPECT_FALSE(m1.Matches(6));
+}
+
+// Tests that NULL can be used in place of Eq(NULL).
+TEST(MatcherTest, CanBeImplicitlyConstructedFromNULL) {
+  Matcher<int*> m1 = nullptr;
+  EXPECT_TRUE(m1.Matches(nullptr));
+  int n = 0;
+  EXPECT_FALSE(m1.Matches(&n));
+}
+
+// Tests that matchers can be constructed from a variable that is not properly
+// defined. This should be illegal, but many users rely on this accidentally.
+struct Undefined {
+  virtual ~Undefined() = 0;
+  static const int kInt = 1;
+};
+
+TEST(MatcherTest, CanBeConstructedFromUndefinedVariable) {
+  Matcher<int> m1 = Undefined::kInt;
+  EXPECT_TRUE(m1.Matches(1));
+  EXPECT_FALSE(m1.Matches(2));
+}
+
+// Test that a matcher parameterized with an abstract class compiles.
+TEST(MatcherTest, CanAcceptAbstractClass) { Matcher<const Undefined&> m = _; }
+
+// Tests that matchers are copyable.
+TEST(MatcherTest, IsCopyable) {
+  // Tests the copy constructor.
+  Matcher<bool> m1 = Eq(false);
+  EXPECT_TRUE(m1.Matches(false));
+  EXPECT_FALSE(m1.Matches(true));
+
+  // Tests the assignment operator.
+  m1 = Eq(true);
+  EXPECT_TRUE(m1.Matches(true));
+  EXPECT_FALSE(m1.Matches(false));
+}
+
+// Tests that Matcher<T>::DescribeTo() calls
+// MatcherInterface<T>::DescribeTo().
+TEST(MatcherTest, CanDescribeItself) {
+  EXPECT_EQ("is an even number", Describe(Matcher<int>(new EvenMatcherImpl)));
+}
+
+// Tests Matcher<T>::MatchAndExplain().
+TEST_P(MatcherTestP, MatchAndExplain) {
+  Matcher<int> m = GreaterThan(0);
+  StringMatchResultListener listener1;
+  EXPECT_TRUE(m.MatchAndExplain(42, &listener1));
+  EXPECT_EQ("which is 42 more than 0", listener1.str());
+
+  StringMatchResultListener listener2;
+  EXPECT_FALSE(m.MatchAndExplain(-9, &listener2));
+  EXPECT_EQ("which is 9 less than 0", listener2.str());
+}
+
+// Tests that a C-string literal can be implicitly converted to a
+// Matcher<std::string> or Matcher<const std::string&>.
+TEST(StringMatcherTest, CanBeImplicitlyConstructedFromCStringLiteral) {
+  Matcher<std::string> m1 = "hi";
+  EXPECT_TRUE(m1.Matches("hi"));
+  EXPECT_FALSE(m1.Matches("hello"));
+
+  Matcher<const std::string&> m2 = "hi";
+  EXPECT_TRUE(m2.Matches("hi"));
+  EXPECT_FALSE(m2.Matches("hello"));
+}
+
+// Tests that a string object can be implicitly converted to a
+// Matcher<std::string> or Matcher<const std::string&>.
+TEST(StringMatcherTest, CanBeImplicitlyConstructedFromString) {
+  Matcher<std::string> m1 = std::string("hi");
+  EXPECT_TRUE(m1.Matches("hi"));
+  EXPECT_FALSE(m1.Matches("hello"));
+
+  Matcher<const std::string&> m2 = std::string("hi");
+  EXPECT_TRUE(m2.Matches("hi"));
+  EXPECT_FALSE(m2.Matches("hello"));
+}
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+// Tests that a C-string literal can be implicitly converted to a
+// Matcher<StringView> or Matcher<const StringView&>.
+TEST(StringViewMatcherTest, CanBeImplicitlyConstructedFromCStringLiteral) {
+  Matcher<internal::StringView> m1 = "cats";
+  EXPECT_TRUE(m1.Matches("cats"));
+  EXPECT_FALSE(m1.Matches("dogs"));
+
+  Matcher<const internal::StringView&> m2 = "cats";
+  EXPECT_TRUE(m2.Matches("cats"));
+  EXPECT_FALSE(m2.Matches("dogs"));
+}
+
+// Tests that a std::string object can be implicitly converted to a
+// Matcher<StringView> or Matcher<const StringView&>.
+TEST(StringViewMatcherTest, CanBeImplicitlyConstructedFromString) {
+  Matcher<internal::StringView> m1 = std::string("cats");
+  EXPECT_TRUE(m1.Matches("cats"));
+  EXPECT_FALSE(m1.Matches("dogs"));
+
+  Matcher<const internal::StringView&> m2 = std::string("cats");
+  EXPECT_TRUE(m2.Matches("cats"));
+  EXPECT_FALSE(m2.Matches("dogs"));
+}
+
+// Tests that a StringView object can be implicitly converted to a
+// Matcher<StringView> or Matcher<const StringView&>.
+TEST(StringViewMatcherTest, CanBeImplicitlyConstructedFromStringView) {
+  Matcher<internal::StringView> m1 = internal::StringView("cats");
+  EXPECT_TRUE(m1.Matches("cats"));
+  EXPECT_FALSE(m1.Matches("dogs"));
+
+  Matcher<const internal::StringView&> m2 = internal::StringView("cats");
+  EXPECT_TRUE(m2.Matches("cats"));
+  EXPECT_FALSE(m2.Matches("dogs"));
+}
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+
+// Tests that a std::reference_wrapper<std::string> object can be implicitly
+// converted to a Matcher<std::string> or Matcher<const std::string&> via Eq().
+TEST(StringMatcherTest,
+     CanBeImplicitlyConstructedFromEqReferenceWrapperString) {
+  std::string value = "cats";
+  Matcher<std::string> m1 = Eq(std::ref(value));
+  EXPECT_TRUE(m1.Matches("cats"));
+  EXPECT_FALSE(m1.Matches("dogs"));
+
+  Matcher<const std::string&> m2 = Eq(std::ref(value));
+  EXPECT_TRUE(m2.Matches("cats"));
+  EXPECT_FALSE(m2.Matches("dogs"));
+}
+
+// Tests that MakeMatcher() constructs a Matcher<T> from a
+// MatcherInterface* without requiring the user to explicitly
+// write the type.
+TEST(MakeMatcherTest, ConstructsMatcherFromMatcherInterface) {
+  const MatcherInterface<int>* dummy_impl = new EvenMatcherImpl;
+  Matcher<int> m = MakeMatcher(dummy_impl);
+}
+
+// Tests that MakePolymorphicMatcher() can construct a polymorphic
+// matcher from its implementation using the old API.
+const int g_bar = 1;
+class ReferencesBarOrIsZeroImpl {
+ public:
+  template <typename T>
+  bool MatchAndExplain(const T& x, MatchResultListener* /* listener */) const {
+    const void* p = &x;
+    return p == &g_bar || x == 0;
+  }
+
+  void DescribeTo(ostream* os) const { *os << "g_bar or zero"; }
+
+  void DescribeNegationTo(ostream* os) const {
+    *os << "doesn't reference g_bar and is not zero";
+  }
+};
+
+// This function verifies that MakePolymorphicMatcher() returns a
+// PolymorphicMatcher<T> where T is the argument's type.
+PolymorphicMatcher<ReferencesBarOrIsZeroImpl> ReferencesBarOrIsZero() {
+  return MakePolymorphicMatcher(ReferencesBarOrIsZeroImpl());
+}
+
+TEST(MakePolymorphicMatcherTest, ConstructsMatcherUsingOldAPI) {
+  // Using a polymorphic matcher to match a reference type.
+  Matcher<const int&> m1 = ReferencesBarOrIsZero();
+  EXPECT_TRUE(m1.Matches(0));
+  // Verifies that the identity of a by-reference argument is preserved.
+  EXPECT_TRUE(m1.Matches(g_bar));
+  EXPECT_FALSE(m1.Matches(1));
+  EXPECT_EQ("g_bar or zero", Describe(m1));
+
+  // Using a polymorphic matcher to match a value type.
+  Matcher<double> m2 = ReferencesBarOrIsZero();
+  EXPECT_TRUE(m2.Matches(0.0));
+  EXPECT_FALSE(m2.Matches(0.1));
+  EXPECT_EQ("g_bar or zero", Describe(m2));
+}
+
+// Tests implementing a polymorphic matcher using MatchAndExplain().
+
+class PolymorphicIsEvenImpl {
+ public:
+  void DescribeTo(ostream* os) const { *os << "is even"; }
+
+  void DescribeNegationTo(ostream* os) const { *os << "is odd"; }
+
+  template <typename T>
+  bool MatchAndExplain(const T& x, MatchResultListener* listener) const {
+    // Verifies that we can stream to the listener directly.
+    *listener << "% " << 2;
+    if (listener->stream() != nullptr) {
+      // Verifies that we can stream to the listener's underlying stream
+      // too.
+      *listener->stream() << " == " << (x % 2);
+    }
+    return (x % 2) == 0;
+  }
+};
+
+PolymorphicMatcher<PolymorphicIsEvenImpl> PolymorphicIsEven() {
+  return MakePolymorphicMatcher(PolymorphicIsEvenImpl());
+}
+
+TEST(MakePolymorphicMatcherTest, ConstructsMatcherUsingNewAPI) {
+  // Using PolymorphicIsEven() as a Matcher<int>.
+  const Matcher<int> m1 = PolymorphicIsEven();
+  EXPECT_TRUE(m1.Matches(42));
+  EXPECT_FALSE(m1.Matches(43));
+  EXPECT_EQ("is even", Describe(m1));
+
+  const Matcher<int> not_m1 = Not(m1);
+  EXPECT_EQ("is odd", Describe(not_m1));
+
+  EXPECT_EQ("% 2 == 0", Explain(m1, 42));
+
+  // Using PolymorphicIsEven() as a Matcher<char>.
+  const Matcher<char> m2 = PolymorphicIsEven();
+  EXPECT_TRUE(m2.Matches('\x42'));
+  EXPECT_FALSE(m2.Matches('\x43'));
+  EXPECT_EQ("is even", Describe(m2));
+
+  const Matcher<char> not_m2 = Not(m2);
+  EXPECT_EQ("is odd", Describe(not_m2));
+
+  EXPECT_EQ("% 2 == 0", Explain(m2, '\x42'));
+}
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(MatcherCastTest);
+
+// Tests that MatcherCast<T>(m) works when m is a polymorphic matcher.
+TEST_P(MatcherCastTestP, FromPolymorphicMatcher) {
+  Matcher<int16_t> m;
+  if (use_gtest_matcher_) {
+    m = MatcherCast<int16_t>(GtestGreaterThan(int64_t{5}));
+  } else {
+    m = MatcherCast<int16_t>(Gt(int64_t{5}));
+  }
+  EXPECT_TRUE(m.Matches(6));
+  EXPECT_FALSE(m.Matches(4));
+}
+
+// For testing casting matchers between compatible types.
+class IntValue {
+ public:
+  // An int can be statically (although not implicitly) cast to a
+  // IntValue.
+  explicit IntValue(int a_value) : value_(a_value) {}
+
+  int value() const { return value_; }
+
+ private:
+  int value_;
+};
+
+// For testing casting matchers between compatible types. This is similar to
+// IntValue, but takes a non-const reference to the value, showing MatcherCast
+// works with such types (and doesn't, for example, use a const ref internally).
+class MutableIntView {
+ public:
+  // An int& can be statically (although not implicitly) cast to a
+  // MutableIntView.
+  explicit MutableIntView(int& a_value) : value_(a_value) {}
+
+  int& value() const { return value_; }
+
+ private:
+  int& value_;
+};
+
+// For testing casting matchers between compatible types.
+bool IsPositiveIntValue(const IntValue& foo) { return foo.value() > 0; }
+
+// For testing casting matchers between compatible types.
+bool IsPositiveMutableIntView(MutableIntView foo) { return foo.value() > 0; }
+
+// Tests that MatcherCast<T>(m) works when m is a Matcher<U> where T
+// can be statically converted to U.
+TEST(MatcherCastTest, FromCompatibleType) {
+  Matcher<double> m1 = Eq(2.0);
+  Matcher<int> m2 = MatcherCast<int>(m1);
+  EXPECT_TRUE(m2.Matches(2));
+  EXPECT_FALSE(m2.Matches(3));
+
+  Matcher<IntValue> m3 = Truly(IsPositiveIntValue);
+  Matcher<int> m4 = MatcherCast<int>(m3);
+  // In the following, the arguments 1 and 0 are statically converted
+  // to IntValue objects, and then tested by the IsPositiveIntValue()
+  // predicate.
+  EXPECT_TRUE(m4.Matches(1));
+  EXPECT_FALSE(m4.Matches(0));
+
+  Matcher<MutableIntView> m5 = Truly(IsPositiveMutableIntView);
+  Matcher<int> m6 = MatcherCast<int>(m5);
+  // In the following, the arguments 1 and 0 are statically converted to
+  // MutableIntView objects, and then tested by the IsPositiveMutableIntView()
+  // predicate.
+  EXPECT_TRUE(m6.Matches(1));
+  EXPECT_FALSE(m6.Matches(0));
+}
+
+// Tests that MatcherCast<T>(m) works when m is a Matcher<const T&>.
+TEST(MatcherCastTest, FromConstReferenceToNonReference) {
+  int n = 0;
+  Matcher<const int&> m1 = Ref(n);
+  Matcher<int> m2 = MatcherCast<int>(m1);
+  int n1 = 0;
+  EXPECT_TRUE(m2.Matches(n));
+  EXPECT_FALSE(m2.Matches(n1));
+}
+
+// Tests that MatcherCast<T&>(m) works when m is a Matcher<const T&>.
+TEST(MatcherCastTest, FromConstReferenceToReference) {
+  int n = 0;
+  Matcher<const int&> m1 = Ref(n);
+  Matcher<int&> m2 = MatcherCast<int&>(m1);
+  int n1 = 0;
+  EXPECT_TRUE(m2.Matches(n));
+  EXPECT_FALSE(m2.Matches(n1));
+}
+
+// Tests that MatcherCast<T>(m) works when m is a Matcher<T&>.
+TEST(MatcherCastTest, FromReferenceToNonReference) {
+  Matcher<int&> m1 = Eq(0);
+  Matcher<int> m2 = MatcherCast<int>(m1);
+  EXPECT_TRUE(m2.Matches(0));
+  EXPECT_FALSE(m2.Matches(1));
+
+  // Of course, reference identity isn't preserved since a copy is required.
+  int n = 0;
+  Matcher<int&> m3 = Ref(n);
+  Matcher<int> m4 = MatcherCast<int>(m3);
+  EXPECT_FALSE(m4.Matches(n));
+}
+
+// Tests that MatcherCast<const T&>(m) works when m is a Matcher<T>.
+TEST(MatcherCastTest, FromNonReferenceToConstReference) {
+  Matcher<int> m1 = Eq(0);
+  Matcher<const int&> m2 = MatcherCast<const int&>(m1);
+  EXPECT_TRUE(m2.Matches(0));
+  EXPECT_FALSE(m2.Matches(1));
+}
+
+// Tests that MatcherCast<T&>(m) works when m is a Matcher<T>.
+TEST(MatcherCastTest, FromNonReferenceToReference) {
+  Matcher<int> m1 = Eq(0);
+  Matcher<int&> m2 = MatcherCast<int&>(m1);
+  int n = 0;
+  EXPECT_TRUE(m2.Matches(n));
+  n = 1;
+  EXPECT_FALSE(m2.Matches(n));
+}
+
+// Tests that MatcherCast<T>(m) works when m is a Matcher<T>.
+TEST(MatcherCastTest, FromSameType) {
+  Matcher<int> m1 = Eq(0);
+  Matcher<int> m2 = MatcherCast<int>(m1);
+  EXPECT_TRUE(m2.Matches(0));
+  EXPECT_FALSE(m2.Matches(1));
+}
+
+// Tests that MatcherCast<T>(m) works when m is a value of the same type as the
+// value type of the Matcher.
+TEST(MatcherCastTest, FromAValue) {
+  Matcher<int> m = MatcherCast<int>(42);
+  EXPECT_TRUE(m.Matches(42));
+  EXPECT_FALSE(m.Matches(239));
+}
+
+// Tests that MatcherCast<T>(m) works when m is a value of the type implicitly
+// convertible to the value type of the Matcher.
+TEST(MatcherCastTest, FromAnImplicitlyConvertibleValue) {
+  const int kExpected = 'c';
+  Matcher<int> m = MatcherCast<int>('c');
+  EXPECT_TRUE(m.Matches(kExpected));
+  EXPECT_FALSE(m.Matches(kExpected + 1));
+}
+
+struct NonImplicitlyConstructibleTypeWithOperatorEq {
+  friend bool operator==(
+      const NonImplicitlyConstructibleTypeWithOperatorEq& /* ignored */,
+      int rhs) {
+    return 42 == rhs;
+  }
+  friend bool operator==(
+      int lhs,
+      const NonImplicitlyConstructibleTypeWithOperatorEq& /* ignored */) {
+    return lhs == 42;
+  }
+};
+
+// Tests that MatcherCast<T>(m) works when m is a neither a matcher nor
+// implicitly convertible to the value type of the Matcher, but the value type
+// of the matcher has operator==() overload accepting m.
+TEST(MatcherCastTest, NonImplicitlyConstructibleTypeWithOperatorEq) {
+  Matcher<NonImplicitlyConstructibleTypeWithOperatorEq> m1 =
+      MatcherCast<NonImplicitlyConstructibleTypeWithOperatorEq>(42);
+  EXPECT_TRUE(m1.Matches(NonImplicitlyConstructibleTypeWithOperatorEq()));
+
+  Matcher<NonImplicitlyConstructibleTypeWithOperatorEq> m2 =
+      MatcherCast<NonImplicitlyConstructibleTypeWithOperatorEq>(239);
+  EXPECT_FALSE(m2.Matches(NonImplicitlyConstructibleTypeWithOperatorEq()));
+
+  // When updating the following lines please also change the comment to
+  // namespace convertible_from_any.
+  Matcher<int> m3 =
+      MatcherCast<int>(NonImplicitlyConstructibleTypeWithOperatorEq());
+  EXPECT_TRUE(m3.Matches(42));
+  EXPECT_FALSE(m3.Matches(239));
+}
+
+// ConvertibleFromAny does not work with MSVC. resulting in
+// error C2440: 'initializing': cannot convert from 'Eq' to 'M'
+// No constructor could take the source type, or constructor overload
+// resolution was ambiguous
+
+#if !defined _MSC_VER
+
+// The below ConvertibleFromAny struct is implicitly constructible from anything
+// and when in the same namespace can interact with other tests. In particular,
+// if it is in the same namespace as other tests and one removes
+//   NonImplicitlyConstructibleTypeWithOperatorEq::operator==(int lhs, ...);
+// then the corresponding test still compiles (and it should not!) by implicitly
+// converting NonImplicitlyConstructibleTypeWithOperatorEq to ConvertibleFromAny
+// in m3.Matcher().
+namespace convertible_from_any {
+// Implicitly convertible from any type.
+struct ConvertibleFromAny {
+  ConvertibleFromAny(int a_value) : value(a_value) {}
+  template <typename T>
+  ConvertibleFromAny(const T& /*a_value*/) : value(-1) {
+    ADD_FAILURE() << "Conversion constructor called";
+  }
+  int value;
+};
+
+bool operator==(const ConvertibleFromAny& a, const ConvertibleFromAny& b) {
+  return a.value == b.value;
+}
+
+ostream& operator<<(ostream& os, const ConvertibleFromAny& a) {
+  return os << a.value;
+}
+
+TEST(MatcherCastTest, ConversionConstructorIsUsed) {
+  Matcher<ConvertibleFromAny> m = MatcherCast<ConvertibleFromAny>(1);
+  EXPECT_TRUE(m.Matches(ConvertibleFromAny(1)));
+  EXPECT_FALSE(m.Matches(ConvertibleFromAny(2)));
+}
+
+TEST(MatcherCastTest, FromConvertibleFromAny) {
+  Matcher<ConvertibleFromAny> m =
+      MatcherCast<ConvertibleFromAny>(Eq(ConvertibleFromAny(1)));
+  EXPECT_TRUE(m.Matches(ConvertibleFromAny(1)));
+  EXPECT_FALSE(m.Matches(ConvertibleFromAny(2)));
+}
+}  // namespace convertible_from_any
+
+#endif  // !defined _MSC_VER
+
+struct IntReferenceWrapper {
+  IntReferenceWrapper(const int& a_value) : value(&a_value) {}
+  const int* value;
+};
+
+// Compared the contained values
+bool operator==(const IntReferenceWrapper& a, const IntReferenceWrapper& b) {
+  return *a.value == *b.value;
+}
+
+TEST(MatcherCastTest, ValueIsCopied) {
+  {
+    // When an IntReferenceWrapper is passed.
+    int n = 42;
+    Matcher<IntReferenceWrapper> m =
+        MatcherCast<IntReferenceWrapper>(IntReferenceWrapper(n));
+    {
+      int value = 42;
+      EXPECT_TRUE(m.Matches(value));
+      value = 10;
+      EXPECT_FALSE(m.Matches(value));
+      // This changes the stored reference.
+      n = 10;
+      EXPECT_TRUE(m.Matches(value));
+    }
+  }
+
+  {
+    // When an int is passed.
+    int n = 42;
+    Matcher<IntReferenceWrapper> m = MatcherCast<IntReferenceWrapper>(n);
+    {
+      int value = 42;
+      EXPECT_TRUE(m.Matches(value));
+      value = 10;
+      EXPECT_FALSE(m.Matches(value));
+      // This does not change the stored int.
+      n = 10;
+      EXPECT_FALSE(m.Matches(value));
+    }
+  }
+}
+
+class Base {
+ public:
+  virtual ~Base() = default;
+  Base() = default;
+
+ private:
+  Base(const Base&) = delete;
+  Base& operator=(const Base&) = delete;
+};
+
+class Derived : public Base {
+ public:
+  Derived() : Base() {}
+  int i;
+};
+
+class OtherDerived : public Base {};
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(SafeMatcherCastTest);
+
+// Tests that SafeMatcherCast<T>(m) works when m is a polymorphic matcher.
+TEST_P(SafeMatcherCastTestP, FromPolymorphicMatcher) {
+  Matcher<char> m2;
+  if (use_gtest_matcher_) {
+    m2 = SafeMatcherCast<char>(GtestGreaterThan(32));
+  } else {
+    m2 = SafeMatcherCast<char>(Gt(32));
+  }
+  EXPECT_TRUE(m2.Matches('A'));
+  EXPECT_FALSE(m2.Matches('\n'));
+}
+
+// Tests that SafeMatcherCast<T>(m) works when m is a Matcher<U> where
+// T and U are arithmetic types and T can be losslessly converted to
+// U.
+TEST(SafeMatcherCastTest, FromLosslesslyConvertibleArithmeticType) {
+  Matcher<double> m1 = DoubleEq(1.0);
+  Matcher<float> m2 = SafeMatcherCast<float>(m1);
+  EXPECT_TRUE(m2.Matches(1.0f));
+  EXPECT_FALSE(m2.Matches(2.0f));
+
+  Matcher<char> m3 = SafeMatcherCast<char>(TypedEq<int>('a'));
+  EXPECT_TRUE(m3.Matches('a'));
+  EXPECT_FALSE(m3.Matches('b'));
+}
+
+// Tests that SafeMatcherCast<T>(m) works when m is a Matcher<U> where T and U
+// are pointers or references to a derived and a base class, correspondingly.
+TEST(SafeMatcherCastTest, FromBaseClass) {
+  Derived d, d2;
+  Matcher<Base*> m1 = Eq(&d);
+  Matcher<Derived*> m2 = SafeMatcherCast<Derived*>(m1);
+  EXPECT_TRUE(m2.Matches(&d));
+  EXPECT_FALSE(m2.Matches(&d2));
+
+  Matcher<Base&> m3 = Ref(d);
+  Matcher<Derived&> m4 = SafeMatcherCast<Derived&>(m3);
+  EXPECT_TRUE(m4.Matches(d));
+  EXPECT_FALSE(m4.Matches(d2));
+}
+
+// Tests that SafeMatcherCast<T>(m) works when m is a Matcher<const T&>.
+TEST(SafeMatcherCastTest, FromConstReferenceToNonReference) {
+  int n = 0;
+  Matcher<const int&> m1 = Ref(n);
+  Matcher<int> m2 = SafeMatcherCast<int>(m1);
+  int n1 = 0;
+  EXPECT_TRUE(m2.Matches(n));
+  EXPECT_FALSE(m2.Matches(n1));
+}
+
+// Tests that SafeMatcherCast<T&>(m) works when m is a Matcher<const T&>.
+TEST(SafeMatcherCastTest, FromConstReferenceToReference) {
+  int n = 0;
+  Matcher<const int&> m1 = Ref(n);
+  Matcher<int&> m2 = SafeMatcherCast<int&>(m1);
+  int n1 = 0;
+  EXPECT_TRUE(m2.Matches(n));
+  EXPECT_FALSE(m2.Matches(n1));
+}
+
+// Tests that MatcherCast<const T&>(m) works when m is a Matcher<T>.
+TEST(SafeMatcherCastTest, FromNonReferenceToConstReference) {
+  Matcher<std::unique_ptr<int>> m1 = IsNull();
+  Matcher<const std::unique_ptr<int>&> m2 =
+      SafeMatcherCast<const std::unique_ptr<int>&>(m1);
+  EXPECT_TRUE(m2.Matches(std::unique_ptr<int>()));
+  EXPECT_FALSE(m2.Matches(std::unique_ptr<int>(new int)));
+}
+
+// Tests that SafeMatcherCast<T&>(m) works when m is a Matcher<T>.
+TEST(SafeMatcherCastTest, FromNonReferenceToReference) {
+  Matcher<int> m1 = Eq(0);
+  Matcher<int&> m2 = SafeMatcherCast<int&>(m1);
+  int n = 0;
+  EXPECT_TRUE(m2.Matches(n));
+  n = 1;
+  EXPECT_FALSE(m2.Matches(n));
+}
+
+// Tests that SafeMatcherCast<T>(m) works when m is a Matcher<T>.
+TEST(SafeMatcherCastTest, FromSameType) {
+  Matcher<int> m1 = Eq(0);
+  Matcher<int> m2 = SafeMatcherCast<int>(m1);
+  EXPECT_TRUE(m2.Matches(0));
+  EXPECT_FALSE(m2.Matches(1));
+}
+
+#if !defined _MSC_VER
+
+namespace convertible_from_any {
+TEST(SafeMatcherCastTest, ConversionConstructorIsUsed) {
+  Matcher<ConvertibleFromAny> m = SafeMatcherCast<ConvertibleFromAny>(1);
+  EXPECT_TRUE(m.Matches(ConvertibleFromAny(1)));
+  EXPECT_FALSE(m.Matches(ConvertibleFromAny(2)));
+}
+
+TEST(SafeMatcherCastTest, FromConvertibleFromAny) {
+  Matcher<ConvertibleFromAny> m =
+      SafeMatcherCast<ConvertibleFromAny>(Eq(ConvertibleFromAny(1)));
+  EXPECT_TRUE(m.Matches(ConvertibleFromAny(1)));
+  EXPECT_FALSE(m.Matches(ConvertibleFromAny(2)));
+}
+}  // namespace convertible_from_any
+
+#endif  // !defined _MSC_VER
+
+TEST(SafeMatcherCastTest, ValueIsNotCopied) {
+  int n = 42;
+  Matcher<IntReferenceWrapper> m = SafeMatcherCast<IntReferenceWrapper>(n);
+  // Verify that the matcher holds a reference to n, not to its temporary copy.
+  EXPECT_TRUE(m.Matches(n));
+}
+
+TEST(ExpectThat, TakesLiterals) {
+  EXPECT_THAT(1, 1);
+  EXPECT_THAT(1.0, 1.0);
+  EXPECT_THAT(std::string(), "");
+}
+
+TEST(ExpectThat, TakesFunctions) {
+  struct Helper {
+    static void Func() {}
+  };
+  void (*func)() = Helper::Func;
+  EXPECT_THAT(func, Helper::Func);
+  EXPECT_THAT(func, &Helper::Func);
+}
+
+// Tests that A<T>() matches any value of type T.
+TEST(ATest, MatchesAnyValue) {
+  // Tests a matcher for a value type.
+  Matcher<double> m1 = A<double>();
+  EXPECT_TRUE(m1.Matches(91.43));
+  EXPECT_TRUE(m1.Matches(-15.32));
+
+  // Tests a matcher for a reference type.
+  int a = 2;
+  int b = -6;
+  Matcher<int&> m2 = A<int&>();
+  EXPECT_TRUE(m2.Matches(a));
+  EXPECT_TRUE(m2.Matches(b));
+}
+
+TEST(ATest, WorksForDerivedClass) {
+  Base base;
+  Derived derived;
+  EXPECT_THAT(&base, A<Base*>());
+  // This shouldn't compile: EXPECT_THAT(&base, A<Derived*>());
+  EXPECT_THAT(&derived, A<Base*>());
+  EXPECT_THAT(&derived, A<Derived*>());
+}
+
+// Tests that A<T>() describes itself properly.
+TEST(ATest, CanDescribeSelf) { EXPECT_EQ("is anything", Describe(A<bool>())); }
+
+// Tests that An<T>() matches any value of type T.
+TEST(AnTest, MatchesAnyValue) {
+  // Tests a matcher for a value type.
+  Matcher<int> m1 = An<int>();
+  EXPECT_TRUE(m1.Matches(9143));
+  EXPECT_TRUE(m1.Matches(-1532));
+
+  // Tests a matcher for a reference type.
+  int a = 2;
+  int b = -6;
+  Matcher<int&> m2 = An<int&>();
+  EXPECT_TRUE(m2.Matches(a));
+  EXPECT_TRUE(m2.Matches(b));
+}
+
+// Tests that An<T>() describes itself properly.
+TEST(AnTest, CanDescribeSelf) { EXPECT_EQ("is anything", Describe(An<int>())); }
+
+// Tests that _ can be used as a matcher for any type and matches any
+// value of that type.
+TEST(UnderscoreTest, MatchesAnyValue) {
+  // Uses _ as a matcher for a value type.
+  Matcher<int> m1 = _;
+  EXPECT_TRUE(m1.Matches(123));
+  EXPECT_TRUE(m1.Matches(-242));
+
+  // Uses _ as a matcher for a reference type.
+  bool a = false;
+  const bool b = true;
+  Matcher<const bool&> m2 = _;
+  EXPECT_TRUE(m2.Matches(a));
+  EXPECT_TRUE(m2.Matches(b));
+}
+
+// Tests that _ describes itself properly.
+TEST(UnderscoreTest, CanDescribeSelf) {
+  Matcher<int> m = _;
+  EXPECT_EQ("is anything", Describe(m));
+}
+
+// Tests that Eq(x) matches any value equal to x.
+TEST(EqTest, MatchesEqualValue) {
+  // 2 C-strings with same content but different addresses.
+  const char a1[] = "hi";
+  const char a2[] = "hi";
+
+  Matcher<const char*> m1 = Eq(a1);
+  EXPECT_TRUE(m1.Matches(a1));
+  EXPECT_FALSE(m1.Matches(a2));
+}
+
+// Tests that Eq(v) describes itself properly.
+
+class Unprintable {
+ public:
+  Unprintable() : c_('a') {}
+
+  bool operator==(const Unprintable& /* rhs */) const { return true; }
+  // -Wunused-private-field: dummy accessor for `c_`.
+  char dummy_c() { return c_; }
+
+ private:
+  char c_;
+};
+
+TEST(EqTest, CanDescribeSelf) {
+  Matcher<Unprintable> m = Eq(Unprintable());
+  EXPECT_EQ("is equal to 1-byte object <61>", Describe(m));
+}
+
+// Tests that Eq(v) can be used to match any type that supports
+// comparing with type T, where T is v's type.
+TEST(EqTest, IsPolymorphic) {
+  Matcher<int> m1 = Eq(1);
+  EXPECT_TRUE(m1.Matches(1));
+  EXPECT_FALSE(m1.Matches(2));
+
+  Matcher<char> m2 = Eq(1);
+  EXPECT_TRUE(m2.Matches('\1'));
+  EXPECT_FALSE(m2.Matches('a'));
+}
+
+// Tests that TypedEq<T>(v) matches values of type T that's equal to v.
+TEST(TypedEqTest, ChecksEqualityForGivenType) {
+  Matcher<char> m1 = TypedEq<char>('a');
+  EXPECT_TRUE(m1.Matches('a'));
+  EXPECT_FALSE(m1.Matches('b'));
+
+  Matcher<int> m2 = TypedEq<int>(6);
+  EXPECT_TRUE(m2.Matches(6));
+  EXPECT_FALSE(m2.Matches(7));
+}
+
+// Tests that TypedEq(v) describes itself properly.
+TEST(TypedEqTest, CanDescribeSelf) {
+  EXPECT_EQ("is equal to 2", Describe(TypedEq<int>(2)));
+}
+
+// Tests that TypedEq<T>(v) has type Matcher<T>.
+
+// Type<T>::IsTypeOf(v) compiles if and only if the type of value v is T, where
+// T is a "bare" type (i.e. not in the form of const U or U&).  If v's type is
+// not T, the compiler will generate a message about "undefined reference".
+template <typename T>
+struct Type {
+  static bool IsTypeOf(const T& /* v */) { return true; }
+
+  template <typename T2>
+  static void IsTypeOf(T2 v);
+};
+
+TEST(TypedEqTest, HasSpecifiedType) {
+  // Verifies that the type of TypedEq<T>(v) is Matcher<T>.
+  Type<Matcher<int>>::IsTypeOf(TypedEq<int>(5));
+  Type<Matcher<double>>::IsTypeOf(TypedEq<double>(5));
+}
+
+// Tests that Ge(v) matches anything >= v.
+TEST(GeTest, ImplementsGreaterThanOrEqual) {
+  Matcher<int> m1 = Ge(0);
+  EXPECT_TRUE(m1.Matches(1));
+  EXPECT_TRUE(m1.Matches(0));
+  EXPECT_FALSE(m1.Matches(-1));
+}
+
+// Tests that Ge(v) describes itself properly.
+TEST(GeTest, CanDescribeSelf) {
+  Matcher<int> m = Ge(5);
+  EXPECT_EQ("is >= 5", Describe(m));
+}
+
+// Tests that Gt(v) matches anything > v.
+TEST(GtTest, ImplementsGreaterThan) {
+  Matcher<double> m1 = Gt(0);
+  EXPECT_TRUE(m1.Matches(1.0));
+  EXPECT_FALSE(m1.Matches(0.0));
+  EXPECT_FALSE(m1.Matches(-1.0));
+}
+
+// Tests that Gt(v) describes itself properly.
+TEST(GtTest, CanDescribeSelf) {
+  Matcher<int> m = Gt(5);
+  EXPECT_EQ("is > 5", Describe(m));
+}
+
+// Tests that Le(v) matches anything <= v.
+TEST(LeTest, ImplementsLessThanOrEqual) {
+  Matcher<char> m1 = Le('b');
+  EXPECT_TRUE(m1.Matches('a'));
+  EXPECT_TRUE(m1.Matches('b'));
+  EXPECT_FALSE(m1.Matches('c'));
+}
+
+// Tests that Le(v) describes itself properly.
+TEST(LeTest, CanDescribeSelf) {
+  Matcher<int> m = Le(5);
+  EXPECT_EQ("is <= 5", Describe(m));
+}
+
+// Tests that Lt(v) matches anything < v.
+TEST(LtTest, ImplementsLessThan) {
+  Matcher<const std::string&> m1 = Lt("Hello");
+  EXPECT_TRUE(m1.Matches("Abc"));
+  EXPECT_FALSE(m1.Matches("Hello"));
+  EXPECT_FALSE(m1.Matches("Hello, world!"));
+}
+
+// Tests that Lt(v) describes itself properly.
+TEST(LtTest, CanDescribeSelf) {
+  Matcher<int> m = Lt(5);
+  EXPECT_EQ("is < 5", Describe(m));
+}
+
+// Tests that Ne(v) matches anything != v.
+TEST(NeTest, ImplementsNotEqual) {
+  Matcher<int> m1 = Ne(0);
+  EXPECT_TRUE(m1.Matches(1));
+  EXPECT_TRUE(m1.Matches(-1));
+  EXPECT_FALSE(m1.Matches(0));
+}
+
+// Tests that Ne(v) describes itself properly.
+TEST(NeTest, CanDescribeSelf) {
+  Matcher<int> m = Ne(5);
+  EXPECT_EQ("isn't equal to 5", Describe(m));
+}
+
+class MoveOnly {
+ public:
+  explicit MoveOnly(int i) : i_(i) {}
+  MoveOnly(const MoveOnly&) = delete;
+  MoveOnly(MoveOnly&&) = default;
+  MoveOnly& operator=(const MoveOnly&) = delete;
+  MoveOnly& operator=(MoveOnly&&) = default;
+
+  bool operator==(const MoveOnly& other) const { return i_ == other.i_; }
+  bool operator!=(const MoveOnly& other) const { return i_ != other.i_; }
+  bool operator<(const MoveOnly& other) const { return i_ < other.i_; }
+  bool operator<=(const MoveOnly& other) const { return i_ <= other.i_; }
+  bool operator>(const MoveOnly& other) const { return i_ > other.i_; }
+  bool operator>=(const MoveOnly& other) const { return i_ >= other.i_; }
+
+ private:
+  int i_;
+};
+
+struct MoveHelper {
+  MOCK_METHOD1(Call, void(MoveOnly));
+};
+
+// Disable this test in VS 2015 (version 14), where it fails when SEH is enabled
+#if defined(_MSC_VER) && (_MSC_VER < 1910)
+TEST(ComparisonBaseTest, DISABLED_WorksWithMoveOnly) {
+#else
+TEST(ComparisonBaseTest, WorksWithMoveOnly) {
+#endif
+  MoveOnly m{0};
+  MoveHelper helper;
+
+  EXPECT_CALL(helper, Call(Eq(ByRef(m))));
+  helper.Call(MoveOnly(0));
+  EXPECT_CALL(helper, Call(Ne(ByRef(m))));
+  helper.Call(MoveOnly(1));
+  EXPECT_CALL(helper, Call(Le(ByRef(m))));
+  helper.Call(MoveOnly(0));
+  EXPECT_CALL(helper, Call(Lt(ByRef(m))));
+  helper.Call(MoveOnly(-1));
+  EXPECT_CALL(helper, Call(Ge(ByRef(m))));
+  helper.Call(MoveOnly(0));
+  EXPECT_CALL(helper, Call(Gt(ByRef(m))));
+  helper.Call(MoveOnly(1));
+}
+
+TEST(IsEmptyTest, MatchesContainer) {
+  const Matcher<std::vector<int>> m = IsEmpty();
+  std::vector<int> a = {};
+  std::vector<int> b = {1};
+  EXPECT_TRUE(m.Matches(a));
+  EXPECT_FALSE(m.Matches(b));
+}
+
+TEST(IsEmptyTest, MatchesStdString) {
+  const Matcher<std::string> m = IsEmpty();
+  std::string a = "z";
+  std::string b = "";
+  EXPECT_FALSE(m.Matches(a));
+  EXPECT_TRUE(m.Matches(b));
+}
+
+TEST(IsEmptyTest, MatchesCString) {
+  const Matcher<const char*> m = IsEmpty();
+  const char a[] = "";
+  const char b[] = "x";
+  EXPECT_TRUE(m.Matches(a));
+  EXPECT_FALSE(m.Matches(b));
+}
+
+// Tests that IsNull() matches any NULL pointer of any type.
+TEST(IsNullTest, MatchesNullPointer) {
+  Matcher<int*> m1 = IsNull();
+  int* p1 = nullptr;
+  int n = 0;
+  EXPECT_TRUE(m1.Matches(p1));
+  EXPECT_FALSE(m1.Matches(&n));
+
+  Matcher<const char*> m2 = IsNull();
+  const char* p2 = nullptr;
+  EXPECT_TRUE(m2.Matches(p2));
+  EXPECT_FALSE(m2.Matches("hi"));
+
+  Matcher<void*> m3 = IsNull();
+  void* p3 = nullptr;
+  EXPECT_TRUE(m3.Matches(p3));
+  EXPECT_FALSE(m3.Matches(reinterpret_cast<void*>(0xbeef)));
+}
+
+TEST(IsNullTest, StdFunction) {
+  const Matcher<std::function<void()>> m = IsNull();
+
+  EXPECT_TRUE(m.Matches(std::function<void()>()));
+  EXPECT_FALSE(m.Matches([] {}));
+}
+
+// Tests that IsNull() describes itself properly.
+TEST(IsNullTest, CanDescribeSelf) {
+  Matcher<int*> m = IsNull();
+  EXPECT_EQ("is NULL", Describe(m));
+  EXPECT_EQ("isn't NULL", DescribeNegation(m));
+}
+
+// Tests that NotNull() matches any non-NULL pointer of any type.
+TEST(NotNullTest, MatchesNonNullPointer) {
+  Matcher<int*> m1 = NotNull();
+  int* p1 = nullptr;
+  int n = 0;
+  EXPECT_FALSE(m1.Matches(p1));
+  EXPECT_TRUE(m1.Matches(&n));
+
+  Matcher<const char*> m2 = NotNull();
+  const char* p2 = nullptr;
+  EXPECT_FALSE(m2.Matches(p2));
+  EXPECT_TRUE(m2.Matches("hi"));
+}
+
+TEST(NotNullTest, LinkedPtr) {
+  const Matcher<std::shared_ptr<int>> m = NotNull();
+  const std::shared_ptr<int> null_p;
+  const std::shared_ptr<int> non_null_p(new int);
+
+  EXPECT_FALSE(m.Matches(null_p));
+  EXPECT_TRUE(m.Matches(non_null_p));
+}
+
+TEST(NotNullTest, ReferenceToConstLinkedPtr) {
+  const Matcher<const std::shared_ptr<double>&> m = NotNull();
+  const std::shared_ptr<double> null_p;
+  const std::shared_ptr<double> non_null_p(new double);
+
+  EXPECT_FALSE(m.Matches(null_p));
+  EXPECT_TRUE(m.Matches(non_null_p));
+}
+
+TEST(NotNullTest, StdFunction) {
+  const Matcher<std::function<void()>> m = NotNull();
+
+  EXPECT_TRUE(m.Matches([] {}));
+  EXPECT_FALSE(m.Matches(std::function<void()>()));
+}
+
+// Tests that NotNull() describes itself properly.
+TEST(NotNullTest, CanDescribeSelf) {
+  Matcher<int*> m = NotNull();
+  EXPECT_EQ("isn't NULL", Describe(m));
+}
+
+// Tests that Ref(variable) matches an argument that references
+// 'variable'.
+TEST(RefTest, MatchesSameVariable) {
+  int a = 0;
+  int b = 0;
+  Matcher<int&> m = Ref(a);
+  EXPECT_TRUE(m.Matches(a));
+  EXPECT_FALSE(m.Matches(b));
+}
+
+// Tests that Ref(variable) describes itself properly.
+TEST(RefTest, CanDescribeSelf) {
+  int n = 5;
+  Matcher<int&> m = Ref(n);
+  stringstream ss;
+  ss << "references the variable @" << &n << " 5";
+  EXPECT_EQ(ss.str(), Describe(m));
+}
+
+// Test that Ref(non_const_varialbe) can be used as a matcher for a
+// const reference.
+TEST(RefTest, CanBeUsedAsMatcherForConstReference) {
+  int a = 0;
+  int b = 0;
+  Matcher<const int&> m = Ref(a);
+  EXPECT_TRUE(m.Matches(a));
+  EXPECT_FALSE(m.Matches(b));
+}
+
+// Tests that Ref(variable) is covariant, i.e. Ref(derived) can be
+// used wherever Ref(base) can be used (Ref(derived) is a sub-type
+// of Ref(base), but not vice versa.
+
+TEST(RefTest, IsCovariant) {
+  Base base, base2;
+  Derived derived;
+  Matcher<const Base&> m1 = Ref(base);
+  EXPECT_TRUE(m1.Matches(base));
+  EXPECT_FALSE(m1.Matches(base2));
+  EXPECT_FALSE(m1.Matches(derived));
+
+  m1 = Ref(derived);
+  EXPECT_TRUE(m1.Matches(derived));
+  EXPECT_FALSE(m1.Matches(base));
+  EXPECT_FALSE(m1.Matches(base2));
+}
+
+TEST(RefTest, ExplainsResult) {
+  int n = 0;
+  EXPECT_THAT(Explain(Matcher<const int&>(Ref(n)), n),
+              StartsWith("which is located @"));
+
+  int m = 0;
+  EXPECT_THAT(Explain(Matcher<const int&>(Ref(n)), m),
+              StartsWith("which is located @"));
+}
+
+// Tests string comparison matchers.
+
+template <typename T = std::string>
+std::string FromStringLike(internal::StringLike<T> str) {
+  return std::string(str);
+}
+
+TEST(StringLike, TestConversions) {
+  EXPECT_EQ("foo", FromStringLike("foo"));
+  EXPECT_EQ("foo", FromStringLike(std::string("foo")));
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  EXPECT_EQ("foo", FromStringLike(internal::StringView("foo")));
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+
+  // Non deducible types.
+  EXPECT_EQ("", FromStringLike({}));
+  EXPECT_EQ("foo", FromStringLike({'f', 'o', 'o'}));
+  const char buf[] = "foo";
+  EXPECT_EQ("foo", FromStringLike({buf, buf + 3}));
+}
+
+TEST(StrEqTest, MatchesEqualString) {
+  Matcher<const char*> m = StrEq(std::string("Hello"));
+  EXPECT_TRUE(m.Matches("Hello"));
+  EXPECT_FALSE(m.Matches("hello"));
+  EXPECT_FALSE(m.Matches(nullptr));
+
+  Matcher<const std::string&> m2 = StrEq("Hello");
+  EXPECT_TRUE(m2.Matches("Hello"));
+  EXPECT_FALSE(m2.Matches("Hi"));
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  Matcher<const internal::StringView&> m3 =
+      StrEq(internal::StringView("Hello"));
+  EXPECT_TRUE(m3.Matches(internal::StringView("Hello")));
+  EXPECT_FALSE(m3.Matches(internal::StringView("hello")));
+  EXPECT_FALSE(m3.Matches(internal::StringView()));
+
+  Matcher<const internal::StringView&> m_empty = StrEq("");
+  EXPECT_TRUE(m_empty.Matches(internal::StringView("")));
+  EXPECT_TRUE(m_empty.Matches(internal::StringView()));
+  EXPECT_FALSE(m_empty.Matches(internal::StringView("hello")));
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+}
+
+TEST(StrEqTest, CanDescribeSelf) {
+  Matcher<std::string> m = StrEq("Hi-\'\"?\\\a\b\f\n\r\t\v\xD3");
+  EXPECT_EQ("is equal to \"Hi-\'\\\"?\\\\\\a\\b\\f\\n\\r\\t\\v\\xD3\"",
+            Describe(m));
+
+  std::string str("01204500800");
+  str[3] = '\0';
+  Matcher<std::string> m2 = StrEq(str);
+  EXPECT_EQ("is equal to \"012\\04500800\"", Describe(m2));
+  str[0] = str[6] = str[7] = str[9] = str[10] = '\0';
+  Matcher<std::string> m3 = StrEq(str);
+  EXPECT_EQ("is equal to \"\\012\\045\\0\\08\\0\\0\"", Describe(m3));
+}
+
+TEST(StrNeTest, MatchesUnequalString) {
+  Matcher<const char*> m = StrNe("Hello");
+  EXPECT_TRUE(m.Matches(""));
+  EXPECT_TRUE(m.Matches(nullptr));
+  EXPECT_FALSE(m.Matches("Hello"));
+
+  Matcher<std::string> m2 = StrNe(std::string("Hello"));
+  EXPECT_TRUE(m2.Matches("hello"));
+  EXPECT_FALSE(m2.Matches("Hello"));
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  Matcher<const internal::StringView> m3 = StrNe(internal::StringView("Hello"));
+  EXPECT_TRUE(m3.Matches(internal::StringView("")));
+  EXPECT_TRUE(m3.Matches(internal::StringView()));
+  EXPECT_FALSE(m3.Matches(internal::StringView("Hello")));
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+}
+
+TEST(StrNeTest, CanDescribeSelf) {
+  Matcher<const char*> m = StrNe("Hi");
+  EXPECT_EQ("isn't equal to \"Hi\"", Describe(m));
+}
+
+TEST(StrCaseEqTest, MatchesEqualStringIgnoringCase) {
+  Matcher<const char*> m = StrCaseEq(std::string("Hello"));
+  EXPECT_TRUE(m.Matches("Hello"));
+  EXPECT_TRUE(m.Matches("hello"));
+  EXPECT_FALSE(m.Matches("Hi"));
+  EXPECT_FALSE(m.Matches(nullptr));
+
+  Matcher<const std::string&> m2 = StrCaseEq("Hello");
+  EXPECT_TRUE(m2.Matches("hello"));
+  EXPECT_FALSE(m2.Matches("Hi"));
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  Matcher<const internal::StringView&> m3 =
+      StrCaseEq(internal::StringView("Hello"));
+  EXPECT_TRUE(m3.Matches(internal::StringView("Hello")));
+  EXPECT_TRUE(m3.Matches(internal::StringView("hello")));
+  EXPECT_FALSE(m3.Matches(internal::StringView("Hi")));
+  EXPECT_FALSE(m3.Matches(internal::StringView()));
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+}
+
+TEST(StrCaseEqTest, MatchesEqualStringWith0IgnoringCase) {
+  std::string str1("oabocdooeoo");
+  std::string str2("OABOCDOOEOO");
+  Matcher<const std::string&> m0 = StrCaseEq(str1);
+  EXPECT_FALSE(m0.Matches(str2 + std::string(1, '\0')));
+
+  str1[3] = str2[3] = '\0';
+  Matcher<const std::string&> m1 = StrCaseEq(str1);
+  EXPECT_TRUE(m1.Matches(str2));
+
+  str1[0] = str1[6] = str1[7] = str1[10] = '\0';
+  str2[0] = str2[6] = str2[7] = str2[10] = '\0';
+  Matcher<const std::string&> m2 = StrCaseEq(str1);
+  str1[9] = str2[9] = '\0';
+  EXPECT_FALSE(m2.Matches(str2));
+
+  Matcher<const std::string&> m3 = StrCaseEq(str1);
+  EXPECT_TRUE(m3.Matches(str2));
+
+  EXPECT_FALSE(m3.Matches(str2 + "x"));
+  str2.append(1, '\0');
+  EXPECT_FALSE(m3.Matches(str2));
+  EXPECT_FALSE(m3.Matches(std::string(str2, 0, 9)));
+}
+
+TEST(StrCaseEqTest, CanDescribeSelf) {
+  Matcher<std::string> m = StrCaseEq("Hi");
+  EXPECT_EQ("is equal to (ignoring case) \"Hi\"", Describe(m));
+}
+
+TEST(StrCaseNeTest, MatchesUnequalStringIgnoringCase) {
+  Matcher<const char*> m = StrCaseNe("Hello");
+  EXPECT_TRUE(m.Matches("Hi"));
+  EXPECT_TRUE(m.Matches(nullptr));
+  EXPECT_FALSE(m.Matches("Hello"));
+  EXPECT_FALSE(m.Matches("hello"));
+
+  Matcher<std::string> m2 = StrCaseNe(std::string("Hello"));
+  EXPECT_TRUE(m2.Matches(""));
+  EXPECT_FALSE(m2.Matches("Hello"));
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  Matcher<const internal::StringView> m3 =
+      StrCaseNe(internal::StringView("Hello"));
+  EXPECT_TRUE(m3.Matches(internal::StringView("Hi")));
+  EXPECT_TRUE(m3.Matches(internal::StringView()));
+  EXPECT_FALSE(m3.Matches(internal::StringView("Hello")));
+  EXPECT_FALSE(m3.Matches(internal::StringView("hello")));
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+}
+
+TEST(StrCaseNeTest, CanDescribeSelf) {
+  Matcher<const char*> m = StrCaseNe("Hi");
+  EXPECT_EQ("isn't equal to (ignoring case) \"Hi\"", Describe(m));
+}
+
+// Tests that HasSubstr() works for matching string-typed values.
+TEST(HasSubstrTest, WorksForStringClasses) {
+  const Matcher<std::string> m1 = HasSubstr("foo");
+  EXPECT_TRUE(m1.Matches(std::string("I love food.")));
+  EXPECT_FALSE(m1.Matches(std::string("tofo")));
+
+  const Matcher<const std::string&> m2 = HasSubstr("foo");
+  EXPECT_TRUE(m2.Matches(std::string("I love food.")));
+  EXPECT_FALSE(m2.Matches(std::string("tofo")));
+
+  const Matcher<std::string> m_empty = HasSubstr("");
+  EXPECT_TRUE(m_empty.Matches(std::string()));
+  EXPECT_TRUE(m_empty.Matches(std::string("not empty")));
+}
+
+// Tests that HasSubstr() works for matching C-string-typed values.
+TEST(HasSubstrTest, WorksForCStrings) {
+  const Matcher<char*> m1 = HasSubstr("foo");
+  EXPECT_TRUE(m1.Matches(const_cast<char*>("I love food.")));
+  EXPECT_FALSE(m1.Matches(const_cast<char*>("tofo")));
+  EXPECT_FALSE(m1.Matches(nullptr));
+
+  const Matcher<const char*> m2 = HasSubstr("foo");
+  EXPECT_TRUE(m2.Matches("I love food."));
+  EXPECT_FALSE(m2.Matches("tofo"));
+  EXPECT_FALSE(m2.Matches(nullptr));
+
+  const Matcher<const char*> m_empty = HasSubstr("");
+  EXPECT_TRUE(m_empty.Matches("not empty"));
+  EXPECT_TRUE(m_empty.Matches(""));
+  EXPECT_FALSE(m_empty.Matches(nullptr));
+}
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+// Tests that HasSubstr() works for matching StringView-typed values.
+TEST(HasSubstrTest, WorksForStringViewClasses) {
+  const Matcher<internal::StringView> m1 =
+      HasSubstr(internal::StringView("foo"));
+  EXPECT_TRUE(m1.Matches(internal::StringView("I love food.")));
+  EXPECT_FALSE(m1.Matches(internal::StringView("tofo")));
+  EXPECT_FALSE(m1.Matches(internal::StringView()));
+
+  const Matcher<const internal::StringView&> m2 = HasSubstr("foo");
+  EXPECT_TRUE(m2.Matches(internal::StringView("I love food.")));
+  EXPECT_FALSE(m2.Matches(internal::StringView("tofo")));
+  EXPECT_FALSE(m2.Matches(internal::StringView()));
+
+  const Matcher<const internal::StringView&> m3 = HasSubstr("");
+  EXPECT_TRUE(m3.Matches(internal::StringView("foo")));
+  EXPECT_TRUE(m3.Matches(internal::StringView("")));
+  EXPECT_TRUE(m3.Matches(internal::StringView()));
+}
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+
+// Tests that HasSubstr(s) describes itself properly.
+TEST(HasSubstrTest, CanDescribeSelf) {
+  Matcher<std::string> m = HasSubstr("foo\n\"");
+  EXPECT_EQ("has substring \"foo\\n\\\"\"", Describe(m));
+}
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(KeyTest);
+
+TEST(KeyTest, CanDescribeSelf) {
+  Matcher<const pair<std::string, int>&> m = Key("foo");
+  EXPECT_EQ("has a key that is equal to \"foo\"", Describe(m));
+  EXPECT_EQ("doesn't have a key that is equal to \"foo\"", DescribeNegation(m));
+}
+
+TEST_P(KeyTestP, ExplainsResult) {
+  Matcher<pair<int, bool>> m = Key(GreaterThan(10));
+  EXPECT_EQ("whose first field is a value which is 5 less than 10",
+            Explain(m, make_pair(5, true)));
+  EXPECT_EQ("whose first field is a value which is 5 more than 10",
+            Explain(m, make_pair(15, true)));
+}
+
+TEST(KeyTest, MatchesCorrectly) {
+  pair<int, std::string> p(25, "foo");
+  EXPECT_THAT(p, Key(25));
+  EXPECT_THAT(p, Not(Key(42)));
+  EXPECT_THAT(p, Key(Ge(20)));
+  EXPECT_THAT(p, Not(Key(Lt(25))));
+}
+
+TEST(KeyTest, WorksWithMoveOnly) {
+  pair<std::unique_ptr<int>, std::unique_ptr<int>> p;
+  EXPECT_THAT(p, Key(Eq(nullptr)));
+}
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(PairTest);
+
+template <size_t I>
+struct Tag {};
+
+struct PairWithGet {
+  int member_1;
+  std::string member_2;
+  using first_type = int;
+  using second_type = std::string;
+
+  const int& GetImpl(Tag<0>) const { return member_1; }
+  const std::string& GetImpl(Tag<1>) const { return member_2; }
+};
+template <size_t I>
+auto get(const PairWithGet& value) -> decltype(value.GetImpl(Tag<I>())) {
+  return value.GetImpl(Tag<I>());
+}
+TEST(PairTest, MatchesPairWithGetCorrectly) {
+  PairWithGet p{25, "foo"};
+  EXPECT_THAT(p, Key(25));
+  EXPECT_THAT(p, Not(Key(42)));
+  EXPECT_THAT(p, Key(Ge(20)));
+  EXPECT_THAT(p, Not(Key(Lt(25))));
+
+  std::vector<PairWithGet> v = {{11, "Foo"}, {29, "gMockIsBestMock"}};
+  EXPECT_THAT(v, Contains(Key(29)));
+}
+
+TEST(KeyTest, SafelyCastsInnerMatcher) {
+  Matcher<int> is_positive = Gt(0);
+  Matcher<int> is_negative = Lt(0);
+  pair<char, bool> p('a', true);
+  EXPECT_THAT(p, Key(is_positive));
+  EXPECT_THAT(p, Not(Key(is_negative)));
+}
+
+TEST(KeyTest, InsideContainsUsingMap) {
+  map<int, char> container;
+  container.insert(make_pair(1, 'a'));
+  container.insert(make_pair(2, 'b'));
+  container.insert(make_pair(4, 'c'));
+  EXPECT_THAT(container, Contains(Key(1)));
+  EXPECT_THAT(container, Not(Contains(Key(3))));
+}
+
+TEST(KeyTest, InsideContainsUsingMultimap) {
+  multimap<int, char> container;
+  container.insert(make_pair(1, 'a'));
+  container.insert(make_pair(2, 'b'));
+  container.insert(make_pair(4, 'c'));
+
+  EXPECT_THAT(container, Not(Contains(Key(25))));
+  container.insert(make_pair(25, 'd'));
+  EXPECT_THAT(container, Contains(Key(25)));
+  container.insert(make_pair(25, 'e'));
+  EXPECT_THAT(container, Contains(Key(25)));
+
+  EXPECT_THAT(container, Contains(Key(1)));
+  EXPECT_THAT(container, Not(Contains(Key(3))));
+}
+
+TEST(PairTest, Typing) {
+  // Test verifies the following type conversions can be compiled.
+  Matcher<const pair<const char*, int>&> m1 = Pair("foo", 42);
+  Matcher<const pair<const char*, int>> m2 = Pair("foo", 42);
+  Matcher<pair<const char*, int>> m3 = Pair("foo", 42);
+
+  Matcher<pair<int, const std::string>> m4 = Pair(25, "42");
+  Matcher<pair<const std::string, int>> m5 = Pair("25", 42);
+}
+
+TEST(PairTest, CanDescribeSelf) {
+  Matcher<const pair<std::string, int>&> m1 = Pair("foo", 42);
+  EXPECT_EQ(
+      "has a first field that is equal to \"foo\""
+      ", and has a second field that is equal to 42",
+      Describe(m1));
+  EXPECT_EQ(
+      "has a first field that isn't equal to \"foo\""
+      ", or has a second field that isn't equal to 42",
+      DescribeNegation(m1));
+  // Double and triple negation (1 or 2 times not and description of negation).
+  Matcher<const pair<int, int>&> m2 = Not(Pair(Not(13), 42));
+  EXPECT_EQ(
+      "has a first field that isn't equal to 13"
+      ", and has a second field that is equal to 42",
+      DescribeNegation(m2));
+}
+
+TEST_P(PairTestP, CanExplainMatchResultTo) {
+  // If neither field matches, Pair() should explain about the first
+  // field.
+  const Matcher<pair<int, int>> m = Pair(GreaterThan(0), GreaterThan(0));
+  EXPECT_EQ("whose first field does not match, which is 1 less than 0",
+            Explain(m, make_pair(-1, -2)));
+
+  // If the first field matches but the second doesn't, Pair() should
+  // explain about the second field.
+  EXPECT_EQ("whose second field does not match, which is 2 less than 0",
+            Explain(m, make_pair(1, -2)));
+
+  // If the first field doesn't match but the second does, Pair()
+  // should explain about the first field.
+  EXPECT_EQ("whose first field does not match, which is 1 less than 0",
+            Explain(m, make_pair(-1, 2)));
+
+  // If both fields match, Pair() should explain about them both.
+  EXPECT_EQ(
+      "whose both fields match, where the first field is a value "
+      "which is 1 more than 0, and the second field is a value "
+      "which is 2 more than 0",
+      Explain(m, make_pair(1, 2)));
+
+  // If only the first match has an explanation, only this explanation should
+  // be printed.
+  const Matcher<pair<int, int>> explain_first = Pair(GreaterThan(0), 0);
+  EXPECT_EQ(
+      "whose both fields match, where the first field is a value "
+      "which is 1 more than 0",
+      Explain(explain_first, make_pair(1, 0)));
+
+  // If only the second match has an explanation, only this explanation should
+  // be printed.
+  const Matcher<pair<int, int>> explain_second = Pair(0, GreaterThan(0));
+  EXPECT_EQ(
+      "whose both fields match, where the second field is a value "
+      "which is 1 more than 0",
+      Explain(explain_second, make_pair(0, 1)));
+}
+
+TEST(PairTest, MatchesCorrectly) {
+  pair<int, std::string> p(25, "foo");
+
+  // Both fields match.
+  EXPECT_THAT(p, Pair(25, "foo"));
+  EXPECT_THAT(p, Pair(Ge(20), HasSubstr("o")));
+
+  // 'first' doesn't match, but 'second' matches.
+  EXPECT_THAT(p, Not(Pair(42, "foo")));
+  EXPECT_THAT(p, Not(Pair(Lt(25), "foo")));
+
+  // 'first' matches, but 'second' doesn't match.
+  EXPECT_THAT(p, Not(Pair(25, "bar")));
+  EXPECT_THAT(p, Not(Pair(25, Not("foo"))));
+
+  // Neither field matches.
+  EXPECT_THAT(p, Not(Pair(13, "bar")));
+  EXPECT_THAT(p, Not(Pair(Lt(13), HasSubstr("a"))));
+}
+
+TEST(PairTest, WorksWithMoveOnly) {
+  pair<std::unique_ptr<int>, std::unique_ptr<int>> p;
+  p.second = std::make_unique<int>(7);
+  EXPECT_THAT(p, Pair(Eq(nullptr), Ne(nullptr)));
+}
+
+TEST(PairTest, SafelyCastsInnerMatchers) {
+  Matcher<int> is_positive = Gt(0);
+  Matcher<int> is_negative = Lt(0);
+  pair<char, bool> p('a', true);
+  EXPECT_THAT(p, Pair(is_positive, _));
+  EXPECT_THAT(p, Not(Pair(is_negative, _)));
+  EXPECT_THAT(p, Pair(_, is_positive));
+  EXPECT_THAT(p, Not(Pair(_, is_negative)));
+}
+
+TEST(PairTest, InsideContainsUsingMap) {
+  map<int, char> container;
+  container.insert(make_pair(1, 'a'));
+  container.insert(make_pair(2, 'b'));
+  container.insert(make_pair(4, 'c'));
+  EXPECT_THAT(container, Contains(Pair(1, 'a')));
+  EXPECT_THAT(container, Contains(Pair(1, _)));
+  EXPECT_THAT(container, Contains(Pair(_, 'a')));
+  EXPECT_THAT(container, Not(Contains(Pair(3, _))));
+}
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(FieldsAreTest);
+
+TEST(FieldsAreTest, MatchesCorrectly) {
+  std::tuple<int, std::string, double> p(25, "foo", .5);
+
+  // All fields match.
+  EXPECT_THAT(p, FieldsAre(25, "foo", .5));
+  EXPECT_THAT(p, FieldsAre(Ge(20), HasSubstr("o"), DoubleEq(.5)));
+
+  // Some don't match.
+  EXPECT_THAT(p, Not(FieldsAre(26, "foo", .5)));
+  EXPECT_THAT(p, Not(FieldsAre(25, "fo", .5)));
+  EXPECT_THAT(p, Not(FieldsAre(25, "foo", .6)));
+}
+
+TEST(FieldsAreTest, CanDescribeSelf) {
+  Matcher<const pair<std::string, int>&> m1 = FieldsAre("foo", 42);
+  EXPECT_EQ(
+      "has field #0 that is equal to \"foo\""
+      ", and has field #1 that is equal to 42",
+      Describe(m1));
+  EXPECT_EQ(
+      "has field #0 that isn't equal to \"foo\""
+      ", or has field #1 that isn't equal to 42",
+      DescribeNegation(m1));
+}
+
+TEST_P(FieldsAreTestP, CanExplainMatchResultTo) {
+  // The first one that fails is the one that gives the error.
+  Matcher<std::tuple<int, int, int>> m =
+      FieldsAre(GreaterThan(0), GreaterThan(0), GreaterThan(0));
+
+  EXPECT_EQ("whose field #0 does not match, which is 1 less than 0",
+            Explain(m, std::make_tuple(-1, -2, -3)));
+  EXPECT_EQ("whose field #1 does not match, which is 2 less than 0",
+            Explain(m, std::make_tuple(1, -2, -3)));
+  EXPECT_EQ("whose field #2 does not match, which is 3 less than 0",
+            Explain(m, std::make_tuple(1, 2, -3)));
+
+  // If they all match, we get a long explanation of success.
+  EXPECT_EQ(
+      "whose all elements match, "
+      "where field #0 is a value which is 1 more than 0"
+      ", and field #1 is a value which is 2 more than 0"
+      ", and field #2 is a value which is 3 more than 0",
+      Explain(m, std::make_tuple(1, 2, 3)));
+
+  // Only print those that have an explanation.
+  m = FieldsAre(GreaterThan(0), 0, GreaterThan(0));
+  EXPECT_EQ(
+      "whose all elements match, "
+      "where field #0 is a value which is 1 more than 0"
+      ", and field #2 is a value which is 3 more than 0",
+      Explain(m, std::make_tuple(1, 0, 3)));
+
+  // If only one has an explanation, then print that one.
+  m = FieldsAre(0, GreaterThan(0), 0);
+  EXPECT_EQ(
+      "whose all elements match, "
+      "where field #1 is a value which is 1 more than 0",
+      Explain(m, std::make_tuple(0, 1, 0)));
+}
+
+#if defined(__cpp_structured_bindings) && __cpp_structured_bindings >= 201606
+TEST(FieldsAreTest, StructuredBindings) {
+  // testing::FieldsAre can also match aggregates and such with C++17 and up.
+  struct MyType {
+    int i;
+    std::string str;
+  };
+  EXPECT_THAT((MyType{17, "foo"}), FieldsAre(Eq(17), HasSubstr("oo")));
+
+  // Test all the supported arities.
+  struct MyVarType1 {
+    int a;
+  };
+  EXPECT_THAT(MyVarType1{}, FieldsAre(0));
+  struct MyVarType2 {
+    int a, b;
+  };
+  EXPECT_THAT(MyVarType2{}, FieldsAre(0, 0));
+  struct MyVarType3 {
+    int a, b, c;
+  };
+  EXPECT_THAT(MyVarType3{}, FieldsAre(0, 0, 0));
+  struct MyVarType4 {
+    int a, b, c, d;
+  };
+  EXPECT_THAT(MyVarType4{}, FieldsAre(0, 0, 0, 0));
+  struct MyVarType5 {
+    int a, b, c, d, e;
+  };
+  EXPECT_THAT(MyVarType5{}, FieldsAre(0, 0, 0, 0, 0));
+  struct MyVarType6 {
+    int a, b, c, d, e, f;
+  };
+  EXPECT_THAT(MyVarType6{}, FieldsAre(0, 0, 0, 0, 0, 0));
+  struct MyVarType7 {
+    int a, b, c, d, e, f, g;
+  };
+  EXPECT_THAT(MyVarType7{}, FieldsAre(0, 0, 0, 0, 0, 0, 0));
+  struct MyVarType8 {
+    int a, b, c, d, e, f, g, h;
+  };
+  EXPECT_THAT(MyVarType8{}, FieldsAre(0, 0, 0, 0, 0, 0, 0, 0));
+  struct MyVarType9 {
+    int a, b, c, d, e, f, g, h, i;
+  };
+  EXPECT_THAT(MyVarType9{}, FieldsAre(0, 0, 0, 0, 0, 0, 0, 0, 0));
+  struct MyVarType10 {
+    int a, b, c, d, e, f, g, h, i, j;
+  };
+  EXPECT_THAT(MyVarType10{}, FieldsAre(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+  struct MyVarType11 {
+    int a, b, c, d, e, f, g, h, i, j, k;
+  };
+  EXPECT_THAT(MyVarType11{}, FieldsAre(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+  struct MyVarType12 {
+    int a, b, c, d, e, f, g, h, i, j, k, l;
+  };
+  EXPECT_THAT(MyVarType12{}, FieldsAre(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+  struct MyVarType13 {
+    int a, b, c, d, e, f, g, h, i, j, k, l, m;
+  };
+  EXPECT_THAT(MyVarType13{}, FieldsAre(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+  struct MyVarType14 {
+    int a, b, c, d, e, f, g, h, i, j, k, l, m, n;
+  };
+  EXPECT_THAT(MyVarType14{},
+              FieldsAre(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+  struct MyVarType15 {
+    int a, b, c, d, e, f, g, h, i, j, k, l, m, n, o;
+  };
+  EXPECT_THAT(MyVarType15{},
+              FieldsAre(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+  struct MyVarType16 {
+    int a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p;
+  };
+  EXPECT_THAT(MyVarType16{},
+              FieldsAre(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+  struct MyVarType17 {
+    int a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q;
+  };
+  EXPECT_THAT(MyVarType17{},
+              FieldsAre(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+  struct MyVarType18 {
+    int a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r;
+  };
+  EXPECT_THAT(MyVarType18{},
+              FieldsAre(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
+  struct MyVarType19 {
+    int a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s;
+  };
+  EXPECT_THAT(MyVarType19{}, FieldsAre(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+                                       0, 0, 0, 0, 0));
+}
+#endif
+
+TEST(PairTest, UseGetInsteadOfMembers) {
+  PairWithGet pair{7, "ABC"};
+  EXPECT_THAT(pair, Pair(7, "ABC"));
+  EXPECT_THAT(pair, Pair(Ge(7), HasSubstr("AB")));
+  EXPECT_THAT(pair, Not(Pair(Lt(7), "ABC")));
+
+  std::vector<PairWithGet> v = {{11, "Foo"}, {29, "gMockIsBestMock"}};
+  EXPECT_THAT(v,
+              ElementsAre(Pair(11, std::string("Foo")), Pair(Ge(10), Not(""))));
+}
+
+// Tests StartsWith(s).
+
+TEST(StartsWithTest, MatchesStringWithGivenPrefix) {
+  const Matcher<const char*> m1 = StartsWith(std::string(""));
+  EXPECT_TRUE(m1.Matches("Hi"));
+  EXPECT_TRUE(m1.Matches(""));
+  EXPECT_FALSE(m1.Matches(nullptr));
+
+  const Matcher<const std::string&> m2 = StartsWith("Hi");
+  EXPECT_TRUE(m2.Matches("Hi"));
+  EXPECT_TRUE(m2.Matches("Hi Hi!"));
+  EXPECT_TRUE(m2.Matches("High"));
+  EXPECT_FALSE(m2.Matches("H"));
+  EXPECT_FALSE(m2.Matches(" Hi"));
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  const Matcher<internal::StringView> m_empty =
+      StartsWith(internal::StringView(""));
+  EXPECT_TRUE(m_empty.Matches(internal::StringView()));
+  EXPECT_TRUE(m_empty.Matches(internal::StringView("")));
+  EXPECT_TRUE(m_empty.Matches(internal::StringView("not empty")));
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+}
+
+TEST(StartsWithTest, CanDescribeSelf) {
+  Matcher<const std::string> m = StartsWith("Hi");
+  EXPECT_EQ("starts with \"Hi\"", Describe(m));
+}
+
+TEST(StartsWithTest, WorksWithStringMatcherOnStringViewMatchee) {
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  EXPECT_THAT(internal::StringView("talk to me goose"),
+              StartsWith(std::string("talk")));
+#else
+  GTEST_SKIP() << "Not applicable without internal::StringView.";
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+}
+
+// Tests EndsWith(s).
+
+TEST(EndsWithTest, MatchesStringWithGivenSuffix) {
+  const Matcher<const char*> m1 = EndsWith("");
+  EXPECT_TRUE(m1.Matches("Hi"));
+  EXPECT_TRUE(m1.Matches(""));
+  EXPECT_FALSE(m1.Matches(nullptr));
+
+  const Matcher<const std::string&> m2 = EndsWith(std::string("Hi"));
+  EXPECT_TRUE(m2.Matches("Hi"));
+  EXPECT_TRUE(m2.Matches("Wow Hi Hi"));
+  EXPECT_TRUE(m2.Matches("Super Hi"));
+  EXPECT_FALSE(m2.Matches("i"));
+  EXPECT_FALSE(m2.Matches("Hi "));
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  const Matcher<const internal::StringView&> m4 =
+      EndsWith(internal::StringView(""));
+  EXPECT_TRUE(m4.Matches("Hi"));
+  EXPECT_TRUE(m4.Matches(""));
+  EXPECT_TRUE(m4.Matches(internal::StringView()));
+  EXPECT_TRUE(m4.Matches(internal::StringView("")));
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+}
+
+TEST(EndsWithTest, CanDescribeSelf) {
+  Matcher<const std::string> m = EndsWith("Hi");
+  EXPECT_EQ("ends with \"Hi\"", Describe(m));
+}
+
+// Tests WhenBase64Unescaped.
+
+TEST(WhenBase64UnescapedTest, MatchesUnescapedBase64Strings) {
+  const Matcher<const char*> m1 = WhenBase64Unescaped(EndsWith("!"));
+  EXPECT_FALSE(m1.Matches("invalid base64"));
+  EXPECT_FALSE(m1.Matches("aGVsbG8gd29ybGQ="));  // hello world
+  EXPECT_TRUE(m1.Matches("aGVsbG8gd29ybGQh"));   // hello world!
+  EXPECT_TRUE(m1.Matches("+/-_IQ"));             // \xfb\xff\xbf!
+
+  const Matcher<const std::string&> m2 = WhenBase64Unescaped(EndsWith("!"));
+  EXPECT_FALSE(m2.Matches("invalid base64"));
+  EXPECT_FALSE(m2.Matches("aGVsbG8gd29ybGQ="));  // hello world
+  EXPECT_TRUE(m2.Matches("aGVsbG8gd29ybGQh"));   // hello world!
+  EXPECT_TRUE(m2.Matches("+/-_IQ"));             // \xfb\xff\xbf!
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  const Matcher<const internal::StringView&> m3 =
+      WhenBase64Unescaped(EndsWith("!"));
+  EXPECT_FALSE(m3.Matches("invalid base64"));
+  EXPECT_FALSE(m3.Matches("aGVsbG8gd29ybGQ="));  // hello world
+  EXPECT_TRUE(m3.Matches("aGVsbG8gd29ybGQh"));   // hello world!
+  EXPECT_TRUE(m3.Matches("+/-_IQ"));             // \xfb\xff\xbf!
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+}
+
+TEST(WhenBase64UnescapedTest, CanDescribeSelf) {
+  const Matcher<const char*> m = WhenBase64Unescaped(EndsWith("!"));
+  EXPECT_EQ("matches after Base64Unescape ends with \"!\"", Describe(m));
+}
+
+// Tests MatchesRegex().
+
+TEST(MatchesRegexTest, MatchesStringMatchingGivenRegex) {
+  const Matcher<const char*> m1 = MatchesRegex("a.*z");
+  EXPECT_TRUE(m1.Matches("az"));
+  EXPECT_TRUE(m1.Matches("abcz"));
+  EXPECT_FALSE(m1.Matches(nullptr));
+
+  const Matcher<const std::string&> m2 = MatchesRegex(new RE("a.*z"));
+  EXPECT_TRUE(m2.Matches("azbz"));
+  EXPECT_FALSE(m2.Matches("az1"));
+  EXPECT_FALSE(m2.Matches("1az"));
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  const Matcher<const internal::StringView&> m3 = MatchesRegex("a.*z");
+  EXPECT_TRUE(m3.Matches(internal::StringView("az")));
+  EXPECT_TRUE(m3.Matches(internal::StringView("abcz")));
+  EXPECT_FALSE(m3.Matches(internal::StringView("1az")));
+  EXPECT_FALSE(m3.Matches(internal::StringView()));
+  const Matcher<const internal::StringView&> m4 =
+      MatchesRegex(internal::StringView(""));
+  EXPECT_TRUE(m4.Matches(internal::StringView("")));
+  EXPECT_TRUE(m4.Matches(internal::StringView()));
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+}
+
+TEST(MatchesRegexTest, CanDescribeSelf) {
+  Matcher<const std::string> m1 = MatchesRegex(std::string("Hi.*"));
+  EXPECT_EQ("matches regular expression \"Hi.*\"", Describe(m1));
+
+  Matcher<const char*> m2 = MatchesRegex(new RE("a.*"));
+  EXPECT_EQ("matches regular expression \"a.*\"", Describe(m2));
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  Matcher<const internal::StringView> m3 = MatchesRegex(new RE("0.*"));
+  EXPECT_EQ("matches regular expression \"0.*\"", Describe(m3));
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+}
+
+// Tests ContainsRegex().
+
+TEST(ContainsRegexTest, MatchesStringContainingGivenRegex) {
+  const Matcher<const char*> m1 = ContainsRegex(std::string("a.*z"));
+  EXPECT_TRUE(m1.Matches("az"));
+  EXPECT_TRUE(m1.Matches("0abcz1"));
+  EXPECT_FALSE(m1.Matches(nullptr));
+
+  const Matcher<const std::string&> m2 = ContainsRegex(new RE("a.*z"));
+  EXPECT_TRUE(m2.Matches("azbz"));
+  EXPECT_TRUE(m2.Matches("az1"));
+  EXPECT_FALSE(m2.Matches("1a"));
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  const Matcher<const internal::StringView&> m3 = ContainsRegex(new RE("a.*z"));
+  EXPECT_TRUE(m3.Matches(internal::StringView("azbz")));
+  EXPECT_TRUE(m3.Matches(internal::StringView("az1")));
+  EXPECT_FALSE(m3.Matches(internal::StringView("1a")));
+  EXPECT_FALSE(m3.Matches(internal::StringView()));
+  const Matcher<const internal::StringView&> m4 =
+      ContainsRegex(internal::StringView(""));
+  EXPECT_TRUE(m4.Matches(internal::StringView("")));
+  EXPECT_TRUE(m4.Matches(internal::StringView()));
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+}
+
+TEST(ContainsRegexTest, CanDescribeSelf) {
+  Matcher<const std::string> m1 = ContainsRegex("Hi.*");
+  EXPECT_EQ("contains regular expression \"Hi.*\"", Describe(m1));
+
+  Matcher<const char*> m2 = ContainsRegex(new RE("a.*"));
+  EXPECT_EQ("contains regular expression \"a.*\"", Describe(m2));
+
+#if GTEST_INTERNAL_HAS_STRING_VIEW
+  Matcher<const internal::StringView> m3 = ContainsRegex(new RE("0.*"));
+  EXPECT_EQ("contains regular expression \"0.*\"", Describe(m3));
+#endif  // GTEST_INTERNAL_HAS_STRING_VIEW
+}
+
+// Tests for wide strings.
+#if GTEST_HAS_STD_WSTRING
+TEST(StdWideStrEqTest, MatchesEqual) {
+  Matcher<const wchar_t*> m = StrEq(::std::wstring(L"Hello"));
+  EXPECT_TRUE(m.Matches(L"Hello"));
+  EXPECT_FALSE(m.Matches(L"hello"));
+  EXPECT_FALSE(m.Matches(nullptr));
+
+  Matcher<const ::std::wstring&> m2 = StrEq(L"Hello");
+  EXPECT_TRUE(m2.Matches(L"Hello"));
+  EXPECT_FALSE(m2.Matches(L"Hi"));
+
+  Matcher<const ::std::wstring&> m3 = StrEq(L"\xD3\x576\x8D3\xC74D");
+  EXPECT_TRUE(m3.Matches(L"\xD3\x576\x8D3\xC74D"));
+  EXPECT_FALSE(m3.Matches(L"\xD3\x576\x8D3\xC74E"));
+
+  ::std::wstring str(L"01204500800");
+  str[3] = L'\0';
+  Matcher<const ::std::wstring&> m4 = StrEq(str);
+  EXPECT_TRUE(m4.Matches(str));
+  str[0] = str[6] = str[7] = str[9] = str[10] = L'\0';
+  Matcher<const ::std::wstring&> m5 = StrEq(str);
+  EXPECT_TRUE(m5.Matches(str));
+}
+
+TEST(StdWideStrEqTest, CanDescribeSelf) {
+  Matcher<::std::wstring> m = StrEq(L"Hi-\'\"?\\\a\b\f\n\r\t\v");
+  EXPECT_EQ("is equal to L\"Hi-\'\\\"?\\\\\\a\\b\\f\\n\\r\\t\\v\"",
+            Describe(m));
+
+  Matcher<::std::wstring> m2 = StrEq(L"\xD3\x576\x8D3\xC74D");
+  EXPECT_EQ("is equal to L\"\\xD3\\x576\\x8D3\\xC74D\"", Describe(m2));
+
+  ::std::wstring str(L"01204500800");
+  str[3] = L'\0';
+  Matcher<const ::std::wstring&> m4 = StrEq(str);
+  EXPECT_EQ("is equal to L\"012\\04500800\"", Describe(m4));
+  str[0] = str[6] = str[7] = str[9] = str[10] = L'\0';
+  Matcher<const ::std::wstring&> m5 = StrEq(str);
+  EXPECT_EQ("is equal to L\"\\012\\045\\0\\08\\0\\0\"", Describe(m5));
+}
+
+TEST(StdWideStrNeTest, MatchesUnequalString) {
+  Matcher<const wchar_t*> m = StrNe(L"Hello");
+  EXPECT_TRUE(m.Matches(L""));
+  EXPECT_TRUE(m.Matches(nullptr));
+  EXPECT_FALSE(m.Matches(L"Hello"));
+
+  Matcher<::std::wstring> m2 = StrNe(::std::wstring(L"Hello"));
+  EXPECT_TRUE(m2.Matches(L"hello"));
+  EXPECT_FALSE(m2.Matches(L"Hello"));
+}
+
+TEST(StdWideStrNeTest, CanDescribeSelf) {
+  Matcher<const wchar_t*> m = StrNe(L"Hi");
+  EXPECT_EQ("isn't equal to L\"Hi\"", Describe(m));
+}
+
+TEST(StdWideStrCaseEqTest, MatchesEqualStringIgnoringCase) {
+  Matcher<const wchar_t*> m = StrCaseEq(::std::wstring(L"Hello"));
+  EXPECT_TRUE(m.Matches(L"Hello"));
+  EXPECT_TRUE(m.Matches(L"hello"));
+  EXPECT_FALSE(m.Matches(L"Hi"));
+  EXPECT_FALSE(m.Matches(nullptr));
+
+  Matcher<const ::std::wstring&> m2 = StrCaseEq(L"Hello");
+  EXPECT_TRUE(m2.Matches(L"hello"));
+  EXPECT_FALSE(m2.Matches(L"Hi"));
+}
+
+TEST(StdWideStrCaseEqTest, MatchesEqualStringWith0IgnoringCase) {
+  ::std::wstring str1(L"oabocdooeoo");
+  ::std::wstring str2(L"OABOCDOOEOO");
+  Matcher<const ::std::wstring&> m0 = StrCaseEq(str1);
+  EXPECT_FALSE(m0.Matches(str2 + ::std::wstring(1, L'\0')));
+
+  str1[3] = str2[3] = L'\0';
+  Matcher<const ::std::wstring&> m1 = StrCaseEq(str1);
+  EXPECT_TRUE(m1.Matches(str2));
+
+  str1[0] = str1[6] = str1[7] = str1[10] = L'\0';
+  str2[0] = str2[6] = str2[7] = str2[10] = L'\0';
+  Matcher<const ::std::wstring&> m2 = StrCaseEq(str1);
+  str1[9] = str2[9] = L'\0';
+  EXPECT_FALSE(m2.Matches(str2));
+
+  Matcher<const ::std::wstring&> m3 = StrCaseEq(str1);
+  EXPECT_TRUE(m3.Matches(str2));
+
+  EXPECT_FALSE(m3.Matches(str2 + L"x"));
+  str2.append(1, L'\0');
+  EXPECT_FALSE(m3.Matches(str2));
+  EXPECT_FALSE(m3.Matches(::std::wstring(str2, 0, 9)));
+}
+
+TEST(StdWideStrCaseEqTest, CanDescribeSelf) {
+  Matcher<::std::wstring> m = StrCaseEq(L"Hi");
+  EXPECT_EQ("is equal to (ignoring case) L\"Hi\"", Describe(m));
+}
+
+TEST(StdWideStrCaseNeTest, MatchesUnequalStringIgnoringCase) {
+  Matcher<const wchar_t*> m = StrCaseNe(L"Hello");
+  EXPECT_TRUE(m.Matches(L"Hi"));
+  EXPECT_TRUE(m.Matches(nullptr));
+  EXPECT_FALSE(m.Matches(L"Hello"));
+  EXPECT_FALSE(m.Matches(L"hello"));
+
+  Matcher<::std::wstring> m2 = StrCaseNe(::std::wstring(L"Hello"));
+  EXPECT_TRUE(m2.Matches(L""));
+  EXPECT_FALSE(m2.Matches(L"Hello"));
+}
+
+TEST(StdWideStrCaseNeTest, CanDescribeSelf) {
+  Matcher<const wchar_t*> m = StrCaseNe(L"Hi");
+  EXPECT_EQ("isn't equal to (ignoring case) L\"Hi\"", Describe(m));
+}
+
+// Tests that HasSubstr() works for matching wstring-typed values.
+TEST(StdWideHasSubstrTest, WorksForStringClasses) {
+  const Matcher<::std::wstring> m1 = HasSubstr(L"foo");
+  EXPECT_TRUE(m1.Matches(::std::wstring(L"I love food.")));
+  EXPECT_FALSE(m1.Matches(::std::wstring(L"tofo")));
+
+  const Matcher<const ::std::wstring&> m2 = HasSubstr(L"foo");
+  EXPECT_TRUE(m2.Matches(::std::wstring(L"I love food.")));
+  EXPECT_FALSE(m2.Matches(::std::wstring(L"tofo")));
+}
+
+// Tests that HasSubstr() works for matching C-wide-string-typed values.
+TEST(StdWideHasSubstrTest, WorksForCStrings) {
+  const Matcher<wchar_t*> m1 = HasSubstr(L"foo");
+  EXPECT_TRUE(m1.Matches(const_cast<wchar_t*>(L"I love food.")));
+  EXPECT_FALSE(m1.Matches(const_cast<wchar_t*>(L"tofo")));
+  EXPECT_FALSE(m1.Matches(nullptr));
+
+  const Matcher<const wchar_t*> m2 = HasSubstr(L"foo");
+  EXPECT_TRUE(m2.Matches(L"I love food."));
+  EXPECT_FALSE(m2.Matches(L"tofo"));
+  EXPECT_FALSE(m2.Matches(nullptr));
+}
+
+// Tests that HasSubstr(s) describes itself properly.
+TEST(StdWideHasSubstrTest, CanDescribeSelf) {
+  Matcher<::std::wstring> m = HasSubstr(L"foo\n\"");
+  EXPECT_EQ("has substring L\"foo\\n\\\"\"", Describe(m));
+}
+
+// Tests StartsWith(s).
+
+TEST(StdWideStartsWithTest, MatchesStringWithGivenPrefix) {
+  const Matcher<const wchar_t*> m1 = StartsWith(::std::wstring(L""));
+  EXPECT_TRUE(m1.Matches(L"Hi"));
+  EXPECT_TRUE(m1.Matches(L""));
+  EXPECT_FALSE(m1.Matches(nullptr));
+
+  const Matcher<const ::std::wstring&> m2 = StartsWith(L"Hi");
+  EXPECT_TRUE(m2.Matches(L"Hi"));
+  EXPECT_TRUE(m2.Matches(L"Hi Hi!"));
+  EXPECT_TRUE(m2.Matches(L"High"));
+  EXPECT_FALSE(m2.Matches(L"H"));
+  EXPECT_FALSE(m2.Matches(L" Hi"));
+}
+
+TEST(StdWideStartsWithTest, CanDescribeSelf) {
+  Matcher<const ::std::wstring> m = StartsWith(L"Hi");
+  EXPECT_EQ("starts with L\"Hi\"", Describe(m));
+}
+
+// Tests EndsWith(s).
+
+TEST(StdWideEndsWithTest, MatchesStringWithGivenSuffix) {
+  const Matcher<const wchar_t*> m1 = EndsWith(L"");
+  EXPECT_TRUE(m1.Matches(L"Hi"));
+  EXPECT_TRUE(m1.Matches(L""));
+  EXPECT_FALSE(m1.Matches(nullptr));
+
+  const Matcher<const ::std::wstring&> m2 = EndsWith(::std::wstring(L"Hi"));
+  EXPECT_TRUE(m2.Matches(L"Hi"));
+  EXPECT_TRUE(m2.Matches(L"Wow Hi Hi"));
+  EXPECT_TRUE(m2.Matches(L"Super Hi"));
+  EXPECT_FALSE(m2.Matches(L"i"));
+  EXPECT_FALSE(m2.Matches(L"Hi "));
+}
+
+TEST(StdWideEndsWithTest, CanDescribeSelf) {
+  Matcher<const ::std::wstring> m = EndsWith(L"Hi");
+  EXPECT_EQ("ends with L\"Hi\"", Describe(m));
+}
+
+#endif  // GTEST_HAS_STD_WSTRING
+
+TEST(ExplainMatchResultTest, WorksWithPolymorphicMatcher) {
+  StringMatchResultListener listener1;
+  EXPECT_TRUE(ExplainMatchResult(PolymorphicIsEven(), 42, &listener1));
+  EXPECT_EQ("% 2 == 0", listener1.str());
+
+  StringMatchResultListener listener2;
+  EXPECT_FALSE(ExplainMatchResult(Ge(42), 1.5, &listener2));
+  EXPECT_EQ("", listener2.str());
+}
+
+TEST(ExplainMatchResultTest, WorksWithMonomorphicMatcher) {
+  const Matcher<int> is_even = PolymorphicIsEven();
+  StringMatchResultListener listener1;
+  EXPECT_TRUE(ExplainMatchResult(is_even, 42, &listener1));
+  EXPECT_EQ("% 2 == 0", listener1.str());
+
+  const Matcher<const double&> is_zero = Eq(0);
+  StringMatchResultListener listener2;
+  EXPECT_FALSE(ExplainMatchResult(is_zero, 1.5, &listener2));
+  EXPECT_EQ("", listener2.str());
+}
+
+MATCHER(ConstructNoArg, "") { return true; }
+MATCHER_P(Construct1Arg, arg1, "") { return true; }
+MATCHER_P2(Construct2Args, arg1, arg2, "") { return true; }
+
+TEST(MatcherConstruct, ExplicitVsImplicit) {
+  {
+    // No arg constructor can be constructed with empty brace.
+    ConstructNoArgMatcher m = {};
+    (void)m;
+    // And with no args
+    ConstructNoArgMatcher m2;
+    (void)m2;
+  }
+  {
+    // The one arg constructor has an explicit constructor.
+    // This is to prevent the implicit conversion.
+    using M = Construct1ArgMatcherP<int>;
+    EXPECT_TRUE((std::is_constructible<M, int>::value));
+    EXPECT_FALSE((std::is_convertible<int, M>::value));
+  }
+  {
+    // Multiple arg matchers can be constructed with an implicit construction.
+    Construct2ArgsMatcherP2<int, double> m = {1, 2.2};
+    (void)m;
+  }
+}
+
+MATCHER_P(Really, inner_matcher, "") {
+  return ExplainMatchResult(inner_matcher, arg, result_listener);
+}
+
+TEST(ExplainMatchResultTest, WorksInsideMATCHER) {
+  EXPECT_THAT(0, Really(Eq(0)));
+}
+
+TEST(DescribeMatcherTest, WorksWithValue) {
+  EXPECT_EQ("is equal to 42", DescribeMatcher<int>(42));
+  EXPECT_EQ("isn't equal to 42", DescribeMatcher<int>(42, true));
+}
+
+TEST(DescribeMatcherTest, WorksWithMonomorphicMatcher) {
+  const Matcher<int> monomorphic = Le(0);
+  EXPECT_EQ("is <= 0", DescribeMatcher<int>(monomorphic));
+  EXPECT_EQ("isn't <= 0", DescribeMatcher<int>(monomorphic, true));
+}
+
+TEST(DescribeMatcherTest, WorksWithPolymorphicMatcher) {
+  EXPECT_EQ("is even", DescribeMatcher<int>(PolymorphicIsEven()));
+  EXPECT_EQ("is odd", DescribeMatcher<int>(PolymorphicIsEven(), true));
+}
+
+MATCHER_P(FieldIIs, inner_matcher, "") {
+  return ExplainMatchResult(inner_matcher, arg.i, result_listener);
+}
+
+#if GTEST_HAS_RTTI
+TEST(WhenDynamicCastToTest, SameType) {
+  Derived derived;
+  derived.i = 4;
+
+  // Right type. A pointer is passed down.
+  Base* as_base_ptr = &derived;
+  EXPECT_THAT(as_base_ptr, WhenDynamicCastTo<Derived*>(Not(IsNull())));
+  EXPECT_THAT(as_base_ptr, WhenDynamicCastTo<Derived*>(Pointee(FieldIIs(4))));
+  EXPECT_THAT(as_base_ptr,
+              Not(WhenDynamicCastTo<Derived*>(Pointee(FieldIIs(5)))));
+}
+
+TEST(WhenDynamicCastToTest, WrongTypes) {
+  Base base;
+  Derived derived;
+  OtherDerived other_derived;
+
+  // Wrong types. NULL is passed.
+  EXPECT_THAT(&base, Not(WhenDynamicCastTo<Derived*>(Pointee(_))));
+  EXPECT_THAT(&base, WhenDynamicCastTo<Derived*>(IsNull()));
+  Base* as_base_ptr = &derived;
+  EXPECT_THAT(as_base_ptr, Not(WhenDynamicCastTo<OtherDerived*>(Pointee(_))));
+  EXPECT_THAT(as_base_ptr, WhenDynamicCastTo<OtherDerived*>(IsNull()));
+  as_base_ptr = &other_derived;
+  EXPECT_THAT(as_base_ptr, Not(WhenDynamicCastTo<Derived*>(Pointee(_))));
+  EXPECT_THAT(as_base_ptr, WhenDynamicCastTo<Derived*>(IsNull()));
+}
+
+TEST(WhenDynamicCastToTest, AlreadyNull) {
+  // Already NULL.
+  Base* as_base_ptr = nullptr;
+  EXPECT_THAT(as_base_ptr, WhenDynamicCastTo<Derived*>(IsNull()));
+}
+
+struct AmbiguousCastTypes {
+  class VirtualDerived : public virtual Base {};
+  class DerivedSub1 : public VirtualDerived {};
+  class DerivedSub2 : public VirtualDerived {};
+  class ManyDerivedInHierarchy : public DerivedSub1, public DerivedSub2 {};
+};
+
+TEST(WhenDynamicCastToTest, AmbiguousCast) {
+  AmbiguousCastTypes::DerivedSub1 sub1;
+  AmbiguousCastTypes::ManyDerivedInHierarchy many_derived;
+  // Multiply derived from Base. dynamic_cast<> returns NULL.
+  Base* as_base_ptr =
+      static_cast<AmbiguousCastTypes::DerivedSub1*>(&many_derived);
+  EXPECT_THAT(as_base_ptr,
+              WhenDynamicCastTo<AmbiguousCastTypes::VirtualDerived*>(IsNull()));
+  as_base_ptr = &sub1;
+  EXPECT_THAT(
+      as_base_ptr,
+      WhenDynamicCastTo<AmbiguousCastTypes::VirtualDerived*>(Not(IsNull())));
+}
+
+TEST(WhenDynamicCastToTest, Describe) {
+  Matcher<Base*> matcher = WhenDynamicCastTo<Derived*>(Pointee(_));
+  const std::string prefix =
+      "when dynamic_cast to " + internal::GetTypeName<Derived*>() + ", ";
+  EXPECT_EQ(prefix + "points to a value that is anything", Describe(matcher));
+  EXPECT_EQ(prefix + "does not point to a value that is anything",
+            DescribeNegation(matcher));
+}
+
+TEST(WhenDynamicCastToTest, Explain) {
+  Matcher<Base*> matcher = WhenDynamicCastTo<Derived*>(Pointee(_));
+  Base* null = nullptr;
+  EXPECT_THAT(Explain(matcher, null), HasSubstr("NULL"));
+  Derived derived;
+  EXPECT_TRUE(matcher.Matches(&derived));
+  EXPECT_THAT(Explain(matcher, &derived), HasSubstr("which points to "));
+
+  // With references, the matcher itself can fail. Test for that one.
+  Matcher<const Base&> ref_matcher = WhenDynamicCastTo<const OtherDerived&>(_);
+  EXPECT_THAT(Explain(ref_matcher, derived),
+              HasSubstr("which cannot be dynamic_cast"));
+}
+
+TEST(WhenDynamicCastToTest, GoodReference) {
+  Derived derived;
+  derived.i = 4;
+  Base& as_base_ref = derived;
+  EXPECT_THAT(as_base_ref, WhenDynamicCastTo<const Derived&>(FieldIIs(4)));
+  EXPECT_THAT(as_base_ref, WhenDynamicCastTo<const Derived&>(Not(FieldIIs(5))));
+}
+
+TEST(WhenDynamicCastToTest, BadReference) {
+  Derived derived;
+  Base& as_base_ref = derived;
+  EXPECT_THAT(as_base_ref, Not(WhenDynamicCastTo<const OtherDerived&>(_)));
+}
+#endif  // GTEST_HAS_RTTI
+
+class DivisibleByImpl {
+ public:
+  explicit DivisibleByImpl(int a_divider) : divider_(a_divider) {}
+
+  // For testing using ExplainMatchResultTo() with polymorphic matchers.
+  template <typename T>
+  bool MatchAndExplain(const T& n, MatchResultListener* listener) const {
+    *listener << "which is " << (n % divider_) << " modulo " << divider_;
+    return (n % divider_) == 0;
+  }
+
+  void DescribeTo(ostream* os) const { *os << "is divisible by " << divider_; }
+
+  void DescribeNegationTo(ostream* os) const {
+    *os << "is not divisible by " << divider_;
+  }
+
+  void set_divider(int a_divider) { divider_ = a_divider; }
+  int divider() const { return divider_; }
+
+ private:
+  int divider_;
+};
+
+PolymorphicMatcher<DivisibleByImpl> DivisibleBy(int n) {
+  return MakePolymorphicMatcher(DivisibleByImpl(n));
+}
+
+// Tests that when AllOf() fails, only the first failing matcher is
+// asked to explain why.
+TEST(ExplainMatchResultTest, AllOf_False_False) {
+  const Matcher<int> m = AllOf(DivisibleBy(4), DivisibleBy(3));
+  EXPECT_EQ("which is 1 modulo 4", Explain(m, 5));
+}
+
+// Tests that when AllOf() fails, only the first failing matcher is
+// asked to explain why.
+TEST(ExplainMatchResultTest, AllOf_False_True) {
+  const Matcher<int> m = AllOf(DivisibleBy(4), DivisibleBy(3));
+  EXPECT_EQ("which is 2 modulo 4", Explain(m, 6));
+}
+
+// Tests that when AllOf() fails, only the first failing matcher is
+// asked to explain why.
+TEST(ExplainMatchResultTest, AllOf_True_False) {
+  const Matcher<int> m = AllOf(Ge(1), DivisibleBy(3));
+  EXPECT_EQ("which is 2 modulo 3", Explain(m, 5));
+}
+
+// Tests that when AllOf() succeeds, all matchers are asked to explain
+// why.
+TEST(ExplainMatchResultTest, AllOf_True_True) {
+  const Matcher<int> m = AllOf(DivisibleBy(2), DivisibleBy(3));
+  EXPECT_EQ("which is 0 modulo 2, and which is 0 modulo 3", Explain(m, 6));
+}
+
+// Tests that when AllOf() succeeds, but matchers have no explanation,
+// the matcher description is used.
+TEST(ExplainMatchResultTest, AllOf_True_True_2) {
+  const Matcher<int> m = AllOf(Ge(2), Le(3));
+  EXPECT_EQ("is >= 2, and is <= 3", Explain(m, 2));
+}
+
+// A matcher that records whether the listener was interested.
+template <typename T>
+class CountingMatcher : public MatcherInterface<T> {
+ public:
+  explicit CountingMatcher(const Matcher<T>& base_matcher,
+                           std::vector<bool>* listener_interested)
+      : base_matcher_(base_matcher),
+        listener_interested_(listener_interested) {}
+
+  bool MatchAndExplain(T x, MatchResultListener* listener) const override {
+    listener_interested_->push_back(listener->IsInterested());
+    return base_matcher_.MatchAndExplain(x, listener);
+  }
+
+  void DescribeTo(ostream* os) const override { base_matcher_.DescribeTo(os); }
+
+ private:
+  Matcher<T> base_matcher_;
+  std::vector<bool>* listener_interested_;
+};
+
+TEST(AllOfTest, DoesNotFormatChildMatchersWhenNotInterested) {
+  std::vector<bool> listener_interested;
+  Matcher<int> matcher =
+      MakeMatcher(new CountingMatcher<int>(Eq(1), &listener_interested));
+  EXPECT_TRUE(matcher.Matches(1));
+  EXPECT_THAT(listener_interested, ElementsAre(false));
+  listener_interested.clear();
+  Matcher<int> all_of_matcher = AllOf(matcher, matcher);
+  EXPECT_TRUE(all_of_matcher.Matches(1));
+  EXPECT_THAT(listener_interested, ElementsAre(false, false));
+  listener_interested.clear();
+  EXPECT_FALSE(all_of_matcher.Matches(0));
+  EXPECT_THAT(listener_interested, ElementsAre(false));
+}
+
+TEST(AnyOfTest, DoesNotFormatChildMatchersWhenNotInterested) {
+  std::vector<bool> listener_interested;
+  Matcher<int> matcher =
+      MakeMatcher(new CountingMatcher<int>(Eq(1), &listener_interested));
+  EXPECT_TRUE(matcher.Matches(1));
+  EXPECT_THAT(listener_interested, ElementsAre(false));
+  listener_interested.clear();
+  Matcher<int> any_of_matcher = AnyOf(matcher, matcher);
+  EXPECT_TRUE(any_of_matcher.Matches(1));
+  EXPECT_THAT(listener_interested, ElementsAre(false));
+  listener_interested.clear();
+  EXPECT_FALSE(any_of_matcher.Matches(0));
+  EXPECT_THAT(listener_interested, ElementsAre(false, false));
+}
+
+TEST(OptionalTest, DoesNotFormatChildMatcherWhenNotInterested) {
+  std::vector<bool> listener_interested;
+  Matcher<int> matcher =
+      MakeMatcher(new CountingMatcher<int>(Eq(1), &listener_interested));
+  EXPECT_TRUE(matcher.Matches(1));
+  EXPECT_THAT(listener_interested, ElementsAre(false));
+  listener_interested.clear();
+  Matcher<std::optional<int>> optional_matcher = Optional(matcher);
+  EXPECT_FALSE(optional_matcher.Matches(std::nullopt));
+  EXPECT_THAT(listener_interested, ElementsAre());
+  EXPECT_TRUE(optional_matcher.Matches(1));
+  EXPECT_THAT(listener_interested, ElementsAre(false));
+  listener_interested.clear();
+  EXPECT_FALSE(matcher.Matches(0));
+  EXPECT_THAT(listener_interested, ElementsAre(false));
+}
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(ExplainmatcherResultTest);
+
+TEST_P(ExplainmatcherResultTestP, MonomorphicMatcher) {
+  const Matcher<int> m = GreaterThan(5);
+  EXPECT_EQ("which is 1 more than 5", Explain(m, 6));
+}
+
+// Tests PolymorphicMatcher::mutable_impl().
+TEST(PolymorphicMatcherTest, CanAccessMutableImpl) {
+  PolymorphicMatcher<DivisibleByImpl> m(DivisibleByImpl(42));
+  DivisibleByImpl& impl = m.mutable_impl();
+  EXPECT_EQ(42, impl.divider());
+
+  impl.set_divider(0);
+  EXPECT_EQ(0, m.mutable_impl().divider());
+}
+
+// Tests PolymorphicMatcher::impl().
+TEST(PolymorphicMatcherTest, CanAccessImpl) {
+  const PolymorphicMatcher<DivisibleByImpl> m(DivisibleByImpl(42));
+  const DivisibleByImpl& impl = m.impl();
+  EXPECT_EQ(42, impl.divider());
+}
+
+}  // namespace
+}  // namespace gmock_matchers_test
+}  // namespace testing
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  // 4244 4100

googletest/googlemock/test/gmock-matchers-containers_test.cc

+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file tests some commonly used argument matchers.
+
+#include <algorithm>
+#include <array>
+#include <cstddef>
+#include <deque>
+#include <forward_list>
+#include <iterator>
+#include <list>
+#include <memory>
+#include <ostream>
+#include <string>
+#include <tuple>
+#include <vector>
+
+#include "gmock/gmock.h"
+#include "test/gmock-matchers_test.h"
+#include "gtest/gtest.h"
+
+// Silence warning C4244: 'initializing': conversion from 'int' to 'short',
+// possible loss of data and C4100, unreferenced local parameter
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4244 4100)
+
+namespace testing {
+namespace gmock_matchers_test {
+namespace {
+
+std::vector<std::unique_ptr<int>> MakeUniquePtrs(const std::vector<int>& ints) {
+  std::vector<std::unique_ptr<int>> pointers;
+  for (int i : ints) pointers.emplace_back(new int(i));
+  return pointers;
+}
+
+std::string OfType(const std::string& type_name) {
+#if GTEST_HAS_RTTI
+  return IsReadableTypeName(type_name) ? " (of type " + type_name + ")" : "";
+#else
+  return "";
+#endif
+}
+
+TEST(ContainsTest, WorksWithMoveOnly) {
+  ContainerHelper helper;
+  EXPECT_CALL(helper, Call(Contains(Pointee(2))));
+  helper.Call(MakeUniquePtrs({1, 2}));
+}
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(ElementsAreTest);
+
+// Tests the variadic version of the ElementsAreMatcher
+TEST(ElementsAreTest, HugeMatcher) {
+  vector<int> test_vector{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};
+
+  EXPECT_THAT(test_vector,
+              ElementsAre(Eq(1), Eq(2), Lt(13), Eq(4), Eq(5), Eq(6), Eq(7),
+                          Eq(8), Eq(9), Eq(10), Gt(1), Eq(12)));
+}
+
+// Tests the variadic version of the UnorderedElementsAreMatcher
+TEST(ElementsAreTest, HugeMatcherStr) {
+  vector<std::string> test_vector{
+      "literal_string", "", "", "", "", "", "", "", "", "", "", ""};
+
+  EXPECT_THAT(test_vector, UnorderedElementsAre("literal_string", _, _, _, _, _,
+                                                _, _, _, _, _, _));
+}
+
+// Tests the variadic version of the UnorderedElementsAreMatcher
+TEST(ElementsAreTest, HugeMatcherUnordered) {
+  vector<int> test_vector{2, 1, 8, 5, 4, 6, 7, 3, 9, 12, 11, 10};
+
+  EXPECT_THAT(test_vector, UnorderedElementsAre(
+                               Eq(2), Eq(1), Gt(7), Eq(5), Eq(4), Eq(6), Eq(7),
+                               Eq(3), Eq(9), Eq(12), Eq(11), Ne(122)));
+}
+
+// Tests that ASSERT_THAT() and EXPECT_THAT() work when the value
+// matches the matcher.
+TEST(MatcherAssertionTest, WorksWhenMatcherIsSatisfied) {
+  ASSERT_THAT(5, Ge(2)) << "This should succeed.";
+  ASSERT_THAT("Foo", EndsWith("oo"));
+  EXPECT_THAT(2, AllOf(Le(7), Ge(0))) << "This should succeed too.";
+  EXPECT_THAT("Hello", StartsWith("Hell"));
+}
+
+// Tests that ASSERT_THAT() and EXPECT_THAT() work when the value
+// doesn't match the matcher.
+TEST(MatcherAssertionTest, WorksWhenMatcherIsNotSatisfied) {
+  // 'n' must be static as it is used in an EXPECT_FATAL_FAILURE(),
+  // which cannot reference auto variables.
+  static unsigned short n;  // NOLINT
+  n = 5;
+
+  EXPECT_FATAL_FAILURE(ASSERT_THAT(n, Gt(10)),
+                       "Value of: n\n"
+                       "Expected: is > 10\n"
+                       "  Actual: 5" +
+                           OfType("unsigned short"));
+  n = 0;
+  EXPECT_NONFATAL_FAILURE(EXPECT_THAT(n, AllOf(Le(7), Ge(5))),
+                          "Value of: n\n"
+                          "Expected: (is <= 7) and (is >= 5)\n"
+                          "  Actual: 0" +
+                              OfType("unsigned short"));
+}
+
+// Tests that ASSERT_THAT() and EXPECT_THAT() work when the argument
+// has a reference type.
+TEST(MatcherAssertionTest, WorksForByRefArguments) {
+  // We use a static variable here as EXPECT_FATAL_FAILURE() cannot
+  // reference auto variables.
+  static int n;
+  n = 0;
+  EXPECT_THAT(n, AllOf(Le(7), Ref(n)));
+  EXPECT_FATAL_FAILURE(ASSERT_THAT(n, Not(Ref(n))),
+                       "Value of: n\n"
+                       "Expected: does not reference the variable @");
+  // Tests the "Actual" part.
+  EXPECT_FATAL_FAILURE(ASSERT_THAT(n, Not(Ref(n))),
+                       "Actual: 0" + OfType("int") + ", which is located @");
+}
+
+// Tests that ASSERT_THAT() and EXPECT_THAT() work when the matcher is
+// monomorphic.
+TEST(MatcherAssertionTest, WorksForMonomorphicMatcher) {
+  Matcher<const char*> starts_with_he = StartsWith("he");
+  ASSERT_THAT("hello", starts_with_he);
+
+  Matcher<const std::string&> ends_with_ok = EndsWith("ok");
+  ASSERT_THAT("book", ends_with_ok);
+  const std::string bad = "bad";
+  EXPECT_NONFATAL_FAILURE(EXPECT_THAT(bad, ends_with_ok),
+                          "Value of: bad\n"
+                          "Expected: ends with \"ok\"\n"
+                          "  Actual: \"bad\"");
+  Matcher<int> is_greater_than_5 = Gt(5);
+  EXPECT_NONFATAL_FAILURE(EXPECT_THAT(5, is_greater_than_5),
+                          "Value of: 5\n"
+                          "Expected: is > 5\n"
+                          "  Actual: 5" +
+                              OfType("int"));
+}
+
+TEST(PointeeTest, RawPointer) {
+  const Matcher<int*> m = Pointee(Ge(0));
+
+  int n = 1;
+  EXPECT_TRUE(m.Matches(&n));
+  n = -1;
+  EXPECT_FALSE(m.Matches(&n));
+  EXPECT_FALSE(m.Matches(nullptr));
+}
+
+TEST(PointeeTest, RawPointerToConst) {
+  const Matcher<const double*> m = Pointee(Ge(0));
+
+  double x = 1;
+  EXPECT_TRUE(m.Matches(&x));
+  x = -1;
+  EXPECT_FALSE(m.Matches(&x));
+  EXPECT_FALSE(m.Matches(nullptr));
+}
+
+TEST(PointeeTest, ReferenceToConstRawPointer) {
+  const Matcher<int* const&> m = Pointee(Ge(0));
+
+  int n = 1;
+  EXPECT_TRUE(m.Matches(&n));
+  n = -1;
+  EXPECT_FALSE(m.Matches(&n));
+  EXPECT_FALSE(m.Matches(nullptr));
+}
+
+TEST(PointeeTest, ReferenceToNonConstRawPointer) {
+  const Matcher<double*&> m = Pointee(Ge(0));
+
+  double x = 1.0;
+  double* p = &x;
+  EXPECT_TRUE(m.Matches(p));
+  x = -1;
+  EXPECT_FALSE(m.Matches(p));
+  p = nullptr;
+  EXPECT_FALSE(m.Matches(p));
+}
+
+TEST(PointeeTest, SmartPointer) {
+  const Matcher<std::unique_ptr<int>> m = Pointee(Ge(0));
+
+  std::unique_ptr<int> n(new int(1));
+  EXPECT_TRUE(m.Matches(n));
+}
+
+TEST(PointeeTest, SmartPointerToConst) {
+  const Matcher<std::unique_ptr<const int>> m = Pointee(Ge(0));
+
+  // There's no implicit conversion from unique_ptr<int> to const
+  // unique_ptr<const int>, so we must pass a unique_ptr<const int> into the
+  // matcher.
+  std::unique_ptr<const int> n(new int(1));
+  EXPECT_TRUE(m.Matches(n));
+}
+
+TEST(PointerTest, RawPointer) {
+  int n = 1;
+  const Matcher<int*> m = Pointer(Eq(&n));
+
+  EXPECT_TRUE(m.Matches(&n));
+
+  int* p = nullptr;
+  EXPECT_FALSE(m.Matches(p));
+  EXPECT_FALSE(m.Matches(nullptr));
+}
+
+TEST(PointerTest, RawPointerToConst) {
+  int n = 1;
+  const Matcher<const int*> m = Pointer(Eq(&n));
+
+  EXPECT_TRUE(m.Matches(&n));
+
+  int* p = nullptr;
+  EXPECT_FALSE(m.Matches(p));
+  EXPECT_FALSE(m.Matches(nullptr));
+}
+
+TEST(PointerTest, SmartPointer) {
+  std::unique_ptr<int> n(new int(10));
+  int* raw_n = n.get();
+  const Matcher<std::unique_ptr<int>> m = Pointer(Eq(raw_n));
+
+  EXPECT_TRUE(m.Matches(n));
+}
+
+TEST(PointerTest, SmartPointerToConst) {
+  std::unique_ptr<const int> n(new int(10));
+  const int* raw_n = n.get();
+  const Matcher<std::unique_ptr<const int>> m = Pointer(Eq(raw_n));
+
+  // There's no implicit conversion from unique_ptr<int> to const
+  // unique_ptr<const int>, so we must pass a unique_ptr<const int> into the
+  // matcher.
+  std::unique_ptr<const int> p(new int(10));
+  EXPECT_FALSE(m.Matches(p));
+}
+
+// Minimal const-propagating pointer.
+template <typename T>
+class ConstPropagatingPtr {
+ public:
+  typedef T element_type;
+
+  ConstPropagatingPtr() : val_() {}
+  explicit ConstPropagatingPtr(T* t) : val_(t) {}
+  ConstPropagatingPtr(const ConstPropagatingPtr& other) : val_(other.val_) {}
+
+  T* get() { return val_; }
+  T& operator*() { return *val_; }
+  // Most smart pointers return non-const T* and T& from the next methods.
+  const T* get() const { return val_; }
+  const T& operator*() const { return *val_; }
+
+ private:
+  T* val_;
+};
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(PointeeTest);
+
+TEST(PointeeTest, WorksWithConstPropagatingPointers) {
+  const Matcher<ConstPropagatingPtr<int>> m = Pointee(Lt(5));
+  int three = 3;
+  const ConstPropagatingPtr<int> co(&three);
+  ConstPropagatingPtr<int> o(&three);
+  EXPECT_TRUE(m.Matches(o));
+  EXPECT_TRUE(m.Matches(co));
+  *o = 6;
+  EXPECT_FALSE(m.Matches(o));
+  EXPECT_FALSE(m.Matches(ConstPropagatingPtr<int>()));
+}
+
+TEST(PointeeTest, NeverMatchesNull) {
+  const Matcher<const char*> m = Pointee(_);
+  EXPECT_FALSE(m.Matches(nullptr));
+}
+
+// Tests that we can write Pointee(value) instead of Pointee(Eq(value)).
+TEST(PointeeTest, MatchesAgainstAValue) {
+  const Matcher<int*> m = Pointee(5);
+
+  int n = 5;
+  EXPECT_TRUE(m.Matches(&n));
+  n = -1;
+  EXPECT_FALSE(m.Matches(&n));
+  EXPECT_FALSE(m.Matches(nullptr));
+}
+
+TEST(PointeeTest, CanDescribeSelf) {
+  const Matcher<int*> m = Pointee(Gt(3));
+  EXPECT_EQ("points to a value that is > 3", Describe(m));
+  EXPECT_EQ("does not point to a value that is > 3", DescribeNegation(m));
+}
+
+TEST_P(PointeeTestP, CanExplainMatchResult) {
+  const Matcher<const std::string*> m = Pointee(StartsWith("Hi"));
+
+  EXPECT_EQ("", Explain(m, static_cast<const std::string*>(nullptr)));
+
+  const Matcher<long*> m2 = Pointee(GreaterThan(1));  // NOLINT
+  long n = 3;                                         // NOLINT
+  EXPECT_EQ("which points to 3" + OfType("long") + ", which is 2 more than 1",
+            Explain(m2, &n));
+}
+
+TEST(PointeeTest, AlwaysExplainsPointee) {
+  const Matcher<int*> m = Pointee(0);
+  int n = 42;
+  EXPECT_EQ("which points to 42" + OfType("int"), Explain(m, &n));
+}
+
+// An uncopyable class.
+class Uncopyable {
+ public:
+  Uncopyable() : value_(-1) {}
+  explicit Uncopyable(int a_value) : value_(a_value) {}
+
+  int value() const { return value_; }
+  void set_value(int i) { value_ = i; }
+
+ private:
+  int value_;
+  Uncopyable(const Uncopyable&) = delete;
+  Uncopyable& operator=(const Uncopyable&) = delete;
+};
+
+// Returns true if and only if x.value() is positive.
+bool ValueIsPositive(const Uncopyable& x) { return x.value() > 0; }
+
+MATCHER_P(UncopyableIs, inner_matcher, "") {
+  return ExplainMatchResult(inner_matcher, arg.value(), result_listener);
+}
+
+// A user-defined struct for testing Field().
+struct AStruct {
+  AStruct() : x(0), y(1.0), z(5), p(nullptr) {}
+  AStruct(const AStruct& rhs)
+      : x(rhs.x), y(rhs.y), z(rhs.z.value()), p(rhs.p) {}
+
+  int x;           // A non-const field.
+  const double y;  // A const field.
+  Uncopyable z;    // An uncopyable field.
+  const char* p;   // A pointer field.
+};
+
+// A derived struct for testing Field().
+struct DerivedStruct : public AStruct {
+  char ch;
+};
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(FieldTest);
+
+// Tests that Field(&Foo::field, ...) works when field is non-const.
+TEST(FieldTest, WorksForNonConstField) {
+  Matcher<AStruct> m = Field(&AStruct::x, Ge(0));
+  Matcher<AStruct> m_with_name = Field("x", &AStruct::x, Ge(0));
+
+  AStruct a;
+  EXPECT_TRUE(m.Matches(a));
+  EXPECT_TRUE(m_with_name.Matches(a));
+  a.x = -1;
+  EXPECT_FALSE(m.Matches(a));
+  EXPECT_FALSE(m_with_name.Matches(a));
+}
+
+// Tests that Field(&Foo::field, ...) works when field is const.
+TEST(FieldTest, WorksForConstField) {
+  AStruct a;
+
+  Matcher<AStruct> m = Field(&AStruct::y, Ge(0.0));
+  Matcher<AStruct> m_with_name = Field("y", &AStruct::y, Ge(0.0));
+  EXPECT_TRUE(m.Matches(a));
+  EXPECT_TRUE(m_with_name.Matches(a));
+  m = Field(&AStruct::y, Le(0.0));
+  m_with_name = Field("y", &AStruct::y, Le(0.0));
+  EXPECT_FALSE(m.Matches(a));
+  EXPECT_FALSE(m_with_name.Matches(a));
+}
+
+// Tests that Field(&Foo::field, ...) works when field is not copyable.
+TEST(FieldTest, WorksForUncopyableField) {
+  AStruct a;
+
+  Matcher<AStruct> m = Field(&AStruct::z, Truly(ValueIsPositive));
+  EXPECT_TRUE(m.Matches(a));
+  m = Field(&AStruct::z, Not(Truly(ValueIsPositive)));
+  EXPECT_FALSE(m.Matches(a));
+}
+
+// Tests that Field(&Foo::field, ...) works when field is a pointer.
+TEST(FieldTest, WorksForPointerField) {
+  // Matching against NULL.
+  Matcher<AStruct> m = Field(&AStruct::p, static_cast<const char*>(nullptr));
+  AStruct a;
+  EXPECT_TRUE(m.Matches(a));
+  a.p = "hi";
+  EXPECT_FALSE(m.Matches(a));
+
+  // Matching a pointer that is not NULL.
+  m = Field(&AStruct::p, StartsWith("hi"));
+  a.p = "hill";
+  EXPECT_TRUE(m.Matches(a));
+  a.p = "hole";
+  EXPECT_FALSE(m.Matches(a));
+}
+
+// Tests that Field() works when the object is passed by reference.
+TEST(FieldTest, WorksForByRefArgument) {
+  Matcher<const AStruct&> m = Field(&AStruct::x, Ge(0));
+
+  AStruct a;
+  EXPECT_TRUE(m.Matches(a));
+  a.x = -1;
+  EXPECT_FALSE(m.Matches(a));
+}
+
+// Tests that Field(&Foo::field, ...) works when the argument's type
+// is a sub-type of Foo.
+TEST(FieldTest, WorksForArgumentOfSubType) {
+  // Note that the matcher expects DerivedStruct but we say AStruct
+  // inside Field().
+  Matcher<const DerivedStruct&> m = Field(&AStruct::x, Ge(0));
+
+  DerivedStruct d;
+  EXPECT_TRUE(m.Matches(d));
+  d.x = -1;
+  EXPECT_FALSE(m.Matches(d));
+}
+
+// Tests that Field(&Foo::field, m) works when field's type and m's
+// argument type are compatible but not the same.
+TEST(FieldTest, WorksForCompatibleMatcherType) {
+  // The field is an int, but the inner matcher expects a signed char.
+  Matcher<const AStruct&> m = Field(&AStruct::x, Matcher<signed char>(Ge(0)));
+
+  AStruct a;
+  EXPECT_TRUE(m.Matches(a));
+  a.x = -1;
+  EXPECT_FALSE(m.Matches(a));
+}
+
+// Tests that Field() can describe itself.
+TEST(FieldTest, CanDescribeSelf) {
+  Matcher<const AStruct&> m = Field(&AStruct::x, Ge(0));
+
+  EXPECT_EQ("is an object whose given field is >= 0", Describe(m));
+  EXPECT_EQ("is an object whose given field isn't >= 0", DescribeNegation(m));
+}
+
+TEST(FieldTest, CanDescribeSelfWithFieldName) {
+  Matcher<const AStruct&> m = Field("field_name", &AStruct::x, Ge(0));
+
+  EXPECT_EQ("is an object whose field `field_name` is >= 0", Describe(m));
+  EXPECT_EQ("is an object whose field `field_name` isn't >= 0",
+            DescribeNegation(m));
+}
+
+// Tests that Field() can explain the match result.
+TEST_P(FieldTestP, CanExplainMatchResult) {
+  Matcher<const AStruct&> m = Field(&AStruct::x, Ge(0));
+
+  AStruct a;
+  a.x = 1;
+  EXPECT_EQ("whose given field is 1" + OfType("int"), Explain(m, a));
+
+  m = Field(&AStruct::x, GreaterThan(0));
+  EXPECT_EQ(
+      "whose given field is 1" + OfType("int") + ", which is 1 more than 0",
+      Explain(m, a));
+}
+
+TEST_P(FieldTestP, CanExplainMatchResultWithFieldName) {
+  Matcher<const AStruct&> m = Field("field_name", &AStruct::x, Ge(0));
+
+  AStruct a;
+  a.x = 1;
+  EXPECT_EQ("whose field `field_name` is 1" + OfType("int"), Explain(m, a));
+
+  m = Field("field_name", &AStruct::x, GreaterThan(0));
+  EXPECT_EQ("whose field `field_name` is 1" + OfType("int") +
+                ", which is 1 more than 0",
+            Explain(m, a));
+}
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(FieldForPointerTest);
+
+// Tests that Field() works when the argument is a pointer to const.
+TEST(FieldForPointerTest, WorksForPointerToConst) {
+  Matcher<const AStruct*> m = Field(&AStruct::x, Ge(0));
+
+  AStruct a;
+  EXPECT_TRUE(m.Matches(&a));
+  a.x = -1;
+  EXPECT_FALSE(m.Matches(&a));
+}
+
+// Tests that Field() works when the argument is a pointer to non-const.
+TEST(FieldForPointerTest, WorksForPointerToNonConst) {
+  Matcher<AStruct*> m = Field(&AStruct::x, Ge(0));
+
+  AStruct a;
+  EXPECT_TRUE(m.Matches(&a));
+  a.x = -1;
+  EXPECT_FALSE(m.Matches(&a));
+}
+
+// Tests that Field() works when the argument is a reference to a const pointer.
+TEST(FieldForPointerTest, WorksForReferenceToConstPointer) {
+  Matcher<AStruct* const&> m = Field(&AStruct::x, Ge(0));
+
+  AStruct a;
+  EXPECT_TRUE(m.Matches(&a));
+  a.x = -1;
+  EXPECT_FALSE(m.Matches(&a));
+}
+
+// Tests that Field() does not match the NULL pointer.
+TEST(FieldForPointerTest, DoesNotMatchNull) {
+  Matcher<const AStruct*> m = Field(&AStruct::x, _);
+  EXPECT_FALSE(m.Matches(nullptr));
+}
+
+// Tests that Field(&Foo::field, ...) works when the argument's type
+// is a sub-type of const Foo*.
+TEST(FieldForPointerTest, WorksForArgumentOfSubType) {
+  // Note that the matcher expects DerivedStruct but we say AStruct
+  // inside Field().
+  Matcher<DerivedStruct*> m = Field(&AStruct::x, Ge(0));
+
+  DerivedStruct d;
+  EXPECT_TRUE(m.Matches(&d));
+  d.x = -1;
+  EXPECT_FALSE(m.Matches(&d));
+}
+
+// Tests that Field() can describe itself when used to match a pointer.
+TEST(FieldForPointerTest, CanDescribeSelf) {
+  Matcher<const AStruct*> m = Field(&AStruct::x, Ge(0));
+
+  EXPECT_EQ("is an object whose given field is >= 0", Describe(m));
+  EXPECT_EQ("is an object whose given field isn't >= 0", DescribeNegation(m));
+}
+
+TEST(FieldForPointerTest, CanDescribeSelfWithFieldName) {
+  Matcher<const AStruct*> m = Field("field_name", &AStruct::x, Ge(0));
+
+  EXPECT_EQ("is an object whose field `field_name` is >= 0", Describe(m));
+  EXPECT_EQ("is an object whose field `field_name` isn't >= 0",
+            DescribeNegation(m));
+}
+
+// Tests that Field() can explain the result of matching a pointer.
+TEST_P(FieldForPointerTestP, CanExplainMatchResult) {
+  Matcher<const AStruct*> m = Field(&AStruct::x, Ge(0));
+
+  AStruct a;
+  a.x = 1;
+  EXPECT_EQ("", Explain(m, static_cast<const AStruct*>(nullptr)));
+  EXPECT_EQ("which points to an object whose given field is 1" + OfType("int"),
+            Explain(m, &a));
+
+  m = Field(&AStruct::x, GreaterThan(0));
+  EXPECT_EQ("which points to an object whose given field is 1" + OfType("int") +
+                ", which is 1 more than 0",
+            Explain(m, &a));
+}
+
+TEST_P(FieldForPointerTestP, CanExplainMatchResultWithFieldName) {
+  Matcher<const AStruct*> m = Field("field_name", &AStruct::x, Ge(0));
+
+  AStruct a;
+  a.x = 1;
+  EXPECT_EQ("", Explain(m, static_cast<const AStruct*>(nullptr)));
+  EXPECT_EQ(
+      "which points to an object whose field `field_name` is 1" + OfType("int"),
+      Explain(m, &a));
+
+  m = Field("field_name", &AStruct::x, GreaterThan(0));
+  EXPECT_EQ("which points to an object whose field `field_name` is 1" +
+                OfType("int") + ", which is 1 more than 0",
+            Explain(m, &a));
+}
+
+// A user-defined class for testing Property().
+class AClass {
+ public:
+  AClass() : n_(0) {}
+
+  // A getter that returns a non-reference.
+  int n() const { return n_; }
+
+  void set_n(int new_n) { n_ = new_n; }
+
+  // A getter that returns a reference to const.
+  const std::string& s() const { return s_; }
+
+  const std::string& s_ref() const& { return s_; }
+
+  void set_s(const std::string& new_s) { s_ = new_s; }
+
+  // A getter that returns a reference to non-const.
+  double& x() const { return x_; }
+
+ private:
+  int n_;
+  std::string s_;
+
+  static double x_;
+};
+
+double AClass::x_ = 0.0;
+
+// A derived class for testing Property().
+class DerivedClass : public AClass {
+ public:
+  int k() const { return k_; }
+
+ private:
+  int k_;
+};
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(PropertyTest);
+
+// Tests that Property(&Foo::property, ...) works when property()
+// returns a non-reference.
+TEST(PropertyTest, WorksForNonReferenceProperty) {
+  Matcher<const AClass&> m = Property(&AClass::n, Ge(0));
+  Matcher<const AClass&> m_with_name = Property("n", &AClass::n, Ge(0));
+
+  AClass a;
+  a.set_n(1);
+  EXPECT_TRUE(m.Matches(a));
+  EXPECT_TRUE(m_with_name.Matches(a));
+
+  a.set_n(-1);
+  EXPECT_FALSE(m.Matches(a));
+  EXPECT_FALSE(m_with_name.Matches(a));
+}
+
+// Tests that Property(&Foo::property, ...) works when property()
+// returns a reference to const.
+TEST(PropertyTest, WorksForReferenceToConstProperty) {
+  Matcher<const AClass&> m = Property(&AClass::s, StartsWith("hi"));
+  Matcher<const AClass&> m_with_name =
+      Property("s", &AClass::s, StartsWith("hi"));
+
+  AClass a;
+  a.set_s("hill");
+  EXPECT_TRUE(m.Matches(a));
+  EXPECT_TRUE(m_with_name.Matches(a));
+
+  a.set_s("hole");
+  EXPECT_FALSE(m.Matches(a));
+  EXPECT_FALSE(m_with_name.Matches(a));
+}
+
+// Tests that Property(&Foo::property, ...) works when property() is
+// ref-qualified.
+TEST(PropertyTest, WorksForRefQualifiedProperty) {
+  Matcher<const AClass&> m = Property(&AClass::s_ref, StartsWith("hi"));
+  Matcher<const AClass&> m_with_name =
+      Property("s", &AClass::s_ref, StartsWith("hi"));
+
+  AClass a;
+  a.set_s("hill");
+  EXPECT_TRUE(m.Matches(a));
+  EXPECT_TRUE(m_with_name.Matches(a));
+
+  a.set_s("hole");
+  EXPECT_FALSE(m.Matches(a));
+  EXPECT_FALSE(m_with_name.Matches(a));
+}
+
+// Tests that Property(&Foo::property, ...) works when property()
+// returns a reference to non-const.
+TEST(PropertyTest, WorksForReferenceToNonConstProperty) {
+  double x = 0.0;
+  AClass a;
+
+  Matcher<const AClass&> m = Property(&AClass::x, Ref(x));
+  EXPECT_FALSE(m.Matches(a));
+
+  m = Property(&AClass::x, Not(Ref(x)));
+  EXPECT_TRUE(m.Matches(a));
+}
+
+// Tests that Property(&Foo::property, ...) works when the argument is
+// passed by value.
+TEST(PropertyTest, WorksForByValueArgument) {
+  Matcher<AClass> m = Property(&AClass::s, StartsWith("hi"));
+
+  AClass a;
+  a.set_s("hill");
+  EXPECT_TRUE(m.Matches(a));
+
+  a.set_s("hole");
+  EXPECT_FALSE(m.Matches(a));
+}
+
+// Tests that Property(&Foo::property, ...) works when the argument's
+// type is a sub-type of Foo.
+TEST(PropertyTest, WorksForArgumentOfSubType) {
+  // The matcher expects a DerivedClass, but inside the Property() we
+  // say AClass.
+  Matcher<const DerivedClass&> m = Property(&AClass::n, Ge(0));
+
+  DerivedClass d;
+  d.set_n(1);
+  EXPECT_TRUE(m.Matches(d));
+
+  d.set_n(-1);
+  EXPECT_FALSE(m.Matches(d));
+}
+
+// Tests that Property(&Foo::property, m) works when property()'s type
+// and m's argument type are compatible but different.
+TEST(PropertyTest, WorksForCompatibleMatcherType) {
+  // n() returns an int but the inner matcher expects a signed char.
+  Matcher<const AClass&> m = Property(&AClass::n, Matcher<signed char>(Ge(0)));
+
+  Matcher<const AClass&> m_with_name =
+      Property("n", &AClass::n, Matcher<signed char>(Ge(0)));
+
+  AClass a;
+  EXPECT_TRUE(m.Matches(a));
+  EXPECT_TRUE(m_with_name.Matches(a));
+  a.set_n(-1);
+  EXPECT_FALSE(m.Matches(a));
+  EXPECT_FALSE(m_with_name.Matches(a));
+}
+
+// Tests that Property() can describe itself.
+TEST(PropertyTest, CanDescribeSelf) {
+  Matcher<const AClass&> m = Property(&AClass::n, Ge(0));
+
+  EXPECT_EQ("is an object whose given property is >= 0", Describe(m));
+  EXPECT_EQ("is an object whose given property isn't >= 0",
+            DescribeNegation(m));
+}
+
+TEST(PropertyTest, CanDescribeSelfWithPropertyName) {
+  Matcher<const AClass&> m = Property("fancy_name", &AClass::n, Ge(0));
+
+  EXPECT_EQ("is an object whose property `fancy_name` is >= 0", Describe(m));
+  EXPECT_EQ("is an object whose property `fancy_name` isn't >= 0",
+            DescribeNegation(m));
+}
+
+// Tests that Property() can explain the match result.
+TEST_P(PropertyTestP, CanExplainMatchResult) {
+  Matcher<const AClass&> m = Property(&AClass::n, Ge(0));
+
+  AClass a;
+  a.set_n(1);
+  EXPECT_EQ("whose given property is 1" + OfType("int"), Explain(m, a));
+
+  m = Property(&AClass::n, GreaterThan(0));
+  EXPECT_EQ(
+      "whose given property is 1" + OfType("int") + ", which is 1 more than 0",
+      Explain(m, a));
+}
+
+TEST_P(PropertyTestP, CanExplainMatchResultWithPropertyName) {
+  Matcher<const AClass&> m = Property("fancy_name", &AClass::n, Ge(0));
+
+  AClass a;
+  a.set_n(1);
+  EXPECT_EQ("whose property `fancy_name` is 1" + OfType("int"), Explain(m, a));
+
+  m = Property("fancy_name", &AClass::n, GreaterThan(0));
+  EXPECT_EQ("whose property `fancy_name` is 1" + OfType("int") +
+                ", which is 1 more than 0",
+            Explain(m, a));
+}
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(PropertyForPointerTest);
+
+// Tests that Property() works when the argument is a pointer to const.
+TEST(PropertyForPointerTest, WorksForPointerToConst) {
+  Matcher<const AClass*> m = Property(&AClass::n, Ge(0));
+
+  AClass a;
+  a.set_n(1);
+  EXPECT_TRUE(m.Matches(&a));
+
+  a.set_n(-1);
+  EXPECT_FALSE(m.Matches(&a));
+}
+
+// Tests that Property() works when the argument is a pointer to non-const.
+TEST(PropertyForPointerTest, WorksForPointerToNonConst) {
+  Matcher<AClass*> m = Property(&AClass::s, StartsWith("hi"));
+
+  AClass a;
+  a.set_s("hill");
+  EXPECT_TRUE(m.Matches(&a));
+
+  a.set_s("hole");
+  EXPECT_FALSE(m.Matches(&a));
+}
+
+// Tests that Property() works when the argument is a reference to a
+// const pointer.
+TEST(PropertyForPointerTest, WorksForReferenceToConstPointer) {
+  Matcher<AClass* const&> m = Property(&AClass::s, StartsWith("hi"));
+
+  AClass a;
+  a.set_s("hill");
+  EXPECT_TRUE(m.Matches(&a));
+
+  a.set_s("hole");
+  EXPECT_FALSE(m.Matches(&a));
+}
+
+// Tests that Property() does not match the NULL pointer.
+TEST(PropertyForPointerTest, WorksForReferenceToNonConstProperty) {
+  Matcher<const AClass*> m = Property(&AClass::x, _);
+  EXPECT_FALSE(m.Matches(nullptr));
+}
+
+// Tests that Property(&Foo::property, ...) works when the argument's
+// type is a sub-type of const Foo*.
+TEST(PropertyForPointerTest, WorksForArgumentOfSubType) {
+  // The matcher expects a DerivedClass, but inside the Property() we
+  // say AClass.
+  Matcher<const DerivedClass*> m = Property(&AClass::n, Ge(0));
+
+  DerivedClass d;
+  d.set_n(1);
+  EXPECT_TRUE(m.Matches(&d));
+
+  d.set_n(-1);
+  EXPECT_FALSE(m.Matches(&d));
+}
+
+// Tests that Property() can describe itself when used to match a pointer.
+TEST(PropertyForPointerTest, CanDescribeSelf) {
+  Matcher<const AClass*> m = Property(&AClass::n, Ge(0));
+
+  EXPECT_EQ("is an object whose given property is >= 0", Describe(m));
+  EXPECT_EQ("is an object whose given property isn't >= 0",
+            DescribeNegation(m));
+}
+
+TEST(PropertyForPointerTest, CanDescribeSelfWithPropertyDescription) {
+  Matcher<const AClass*> m = Property("fancy_name", &AClass::n, Ge(0));
+
+  EXPECT_EQ("is an object whose property `fancy_name` is >= 0", Describe(m));
+  EXPECT_EQ("is an object whose property `fancy_name` isn't >= 0",
+            DescribeNegation(m));
+}
+
+// Tests that Property() can explain the result of matching a pointer.
+TEST_P(PropertyForPointerTestP, CanExplainMatchResult) {
+  Matcher<const AClass*> m = Property(&AClass::n, Ge(0));
+
+  AClass a;
+  a.set_n(1);
+  EXPECT_EQ("", Explain(m, static_cast<const AClass*>(nullptr)));
+  EXPECT_EQ(
+      "which points to an object whose given property is 1" + OfType("int"),
+      Explain(m, &a));
+
+  m = Property(&AClass::n, GreaterThan(0));
+  EXPECT_EQ("which points to an object whose given property is 1" +
+                OfType("int") + ", which is 1 more than 0",
+            Explain(m, &a));
+}
+
+TEST_P(PropertyForPointerTestP, CanExplainMatchResultWithPropertyName) {
+  Matcher<const AClass*> m = Property("fancy_name", &AClass::n, Ge(0));
+
+  AClass a;
+  a.set_n(1);
+  EXPECT_EQ("", Explain(m, static_cast<const AClass*>(nullptr)));
+  EXPECT_EQ("which points to an object whose property `fancy_name` is 1" +
+                OfType("int"),
+            Explain(m, &a));
+
+  m = Property("fancy_name", &AClass::n, GreaterThan(0));
+  EXPECT_EQ("which points to an object whose property `fancy_name` is 1" +
+                OfType("int") + ", which is 1 more than 0",
+            Explain(m, &a));
+}
+
+// Tests ResultOf.
+
+// Tests that ResultOf(f, ...) compiles and works as expected when f is a
+// function pointer.
+std::string IntToStringFunction(int input) {
+  return input == 1 ? "foo" : "bar";
+}
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(ResultOfTest);
+
+TEST(ResultOfTest, WorksForFunctionPointers) {
+  Matcher<int> matcher = ResultOf(&IntToStringFunction, Eq(std::string("foo")));
+
+  EXPECT_TRUE(matcher.Matches(1));
+  EXPECT_FALSE(matcher.Matches(2));
+}
+
+// Tests that ResultOf() can describe itself.
+TEST(ResultOfTest, CanDescribeItself) {
+  Matcher<int> matcher = ResultOf(&IntToStringFunction, StrEq("foo"));
+
+  EXPECT_EQ(
+      "is mapped by the given callable to a value that "
+      "is equal to \"foo\"",
+      Describe(matcher));
+  EXPECT_EQ(
+      "is mapped by the given callable to a value that "
+      "isn't equal to \"foo\"",
+      DescribeNegation(matcher));
+}
+
+// Tests that ResultOf() can describe itself when provided a result description.
+TEST(ResultOfTest, CanDescribeItselfWithResultDescription) {
+  Matcher<int> matcher =
+      ResultOf("string conversion", &IntToStringFunction, StrEq("foo"));
+
+  EXPECT_EQ("whose string conversion is equal to \"foo\"", Describe(matcher));
+  EXPECT_EQ("whose string conversion isn't equal to \"foo\"",
+            DescribeNegation(matcher));
+}
+
+// Tests that ResultOf() can explain the match result.
+int IntFunction(int input) { return input == 42 ? 80 : 90; }
+
+TEST_P(ResultOfTestP, CanExplainMatchResult) {
+  Matcher<int> matcher = ResultOf(&IntFunction, Ge(85));
+  EXPECT_EQ("which is mapped by the given callable to 90" + OfType("int"),
+            Explain(matcher, 36));
+
+  matcher = ResultOf(&IntFunction, GreaterThan(85));
+  EXPECT_EQ("which is mapped by the given callable to 90" + OfType("int") +
+                ", which is 5 more than 85",
+            Explain(matcher, 36));
+}
+
+TEST_P(ResultOfTestP, CanExplainMatchResultWithResultDescription) {
+  Matcher<int> matcher = ResultOf("magic int conversion", &IntFunction, Ge(85));
+  EXPECT_EQ("whose magic int conversion is 90" + OfType("int"),
+            Explain(matcher, 36));
+
+  matcher = ResultOf("magic int conversion", &IntFunction, GreaterThan(85));
+  EXPECT_EQ("whose magic int conversion is 90" + OfType("int") +
+                ", which is 5 more than 85",
+            Explain(matcher, 36));
+}
+
+// Tests that ResultOf(f, ...) compiles and works as expected when f(x)
+// returns a non-reference.
+TEST(ResultOfTest, WorksForNonReferenceResults) {
+  Matcher<int> matcher = ResultOf(&IntFunction, Eq(80));
+
+  EXPECT_TRUE(matcher.Matches(42));
+  EXPECT_FALSE(matcher.Matches(36));
+}
+
+// Tests that ResultOf(f, ...) compiles and works as expected when f(x)
+// returns a reference to non-const.
+double& DoubleFunction(double& input) { return input; }  // NOLINT
+
+Uncopyable& RefUncopyableFunction(Uncopyable& obj) {  // NOLINT
+  return obj;
+}
+
+TEST(ResultOfTest, WorksForReferenceToNonConstResults) {
+  double x = 3.14;
+  double x2 = x;
+  Matcher<double&> matcher = ResultOf(&DoubleFunction, Ref(x));
+
+  EXPECT_TRUE(matcher.Matches(x));
+  EXPECT_FALSE(matcher.Matches(x2));
+
+  // Test that ResultOf works with uncopyable objects
+  Uncopyable obj(0);
+  Uncopyable obj2(0);
+  Matcher<Uncopyable&> matcher2 = ResultOf(&RefUncopyableFunction, Ref(obj));
+
+  EXPECT_TRUE(matcher2.Matches(obj));
+  EXPECT_FALSE(matcher2.Matches(obj2));
+}
+
+// Tests that ResultOf(f, ...) compiles and works as expected when f(x)
+// returns a reference to const.
+const std::string& StringFunction(const std::string& input) { return input; }
+
+TEST(ResultOfTest, WorksForReferenceToConstResults) {
+  std::string s = "foo";
+  std::string s2 = s;
+  Matcher<const std::string&> matcher = ResultOf(&StringFunction, Ref(s));
+
+  EXPECT_TRUE(matcher.Matches(s));
+  EXPECT_FALSE(matcher.Matches(s2));
+}
+
+// Tests that ResultOf(f, m) works when f(x) and m's
+// argument types are compatible but different.
+TEST(ResultOfTest, WorksForCompatibleMatcherTypes) {
+  // IntFunction() returns int but the inner matcher expects a signed char.
+  Matcher<int> matcher = ResultOf(IntFunction, Matcher<signed char>(Ge(85)));
+
+  EXPECT_TRUE(matcher.Matches(36));
+  EXPECT_FALSE(matcher.Matches(42));
+}
+
+// Tests that the program aborts when ResultOf is passed
+// a NULL function pointer.
+TEST(ResultOfDeathTest, DiesOnNullFunctionPointers) {
+  EXPECT_DEATH_IF_SUPPORTED(
+      ResultOf(static_cast<std::string (*)(int dummy)>(nullptr),
+               Eq(std::string("foo"))),
+      "NULL function pointer is passed into ResultOf\\(\\)\\.");
+}
+
+// Tests that ResultOf(f, ...) compiles and works as expected when f is a
+// function reference.
+TEST(ResultOfTest, WorksForFunctionReferences) {
+  Matcher<int> matcher = ResultOf(IntToStringFunction, StrEq("foo"));
+  EXPECT_TRUE(matcher.Matches(1));
+  EXPECT_FALSE(matcher.Matches(2));
+}
+
+// Tests that ResultOf(f, ...) compiles and works as expected when f is a
+// function object.
+struct Functor {
+  std::string operator()(int input) const { return IntToStringFunction(input); }
+};
+
+TEST(ResultOfTest, WorksForFunctors) {
+  Matcher<int> matcher = ResultOf(Functor(), Eq(std::string("foo")));
+
+  EXPECT_TRUE(matcher.Matches(1));
+  EXPECT_FALSE(matcher.Matches(2));
+}
+
+// Tests that ResultOf(f, ...) compiles and works as expected when f is a
+// functor with more than one operator() defined. ResultOf() must work
+// for each defined operator().
+struct PolymorphicFunctor {
+  typedef int result_type;
+  int operator()(int n) { return n; }
+  int operator()(const char* s) { return static_cast<int>(strlen(s)); }
+  std::string operator()(int* p) { return p ? "good ptr" : "null"; }
+};
+
+TEST(ResultOfTest, WorksForPolymorphicFunctors) {
+  Matcher<int> matcher_int = ResultOf(PolymorphicFunctor(), Ge(5));
+
+  EXPECT_TRUE(matcher_int.Matches(10));
+  EXPECT_FALSE(matcher_int.Matches(2));
+
+  Matcher<const char*> matcher_string = ResultOf(PolymorphicFunctor(), Ge(5));
+
+  EXPECT_TRUE(matcher_string.Matches("long string"));
+  EXPECT_FALSE(matcher_string.Matches("shrt"));
+}
+
+TEST(ResultOfTest, WorksForPolymorphicFunctorsIgnoringResultType) {
+  Matcher<int*> matcher = ResultOf(PolymorphicFunctor(), "good ptr");
+
+  int n = 0;
+  EXPECT_TRUE(matcher.Matches(&n));
+  EXPECT_FALSE(matcher.Matches(nullptr));
+}
+
+TEST(ResultOfTest, WorksForLambdas) {
+  Matcher<int> matcher = ResultOf(
+      [](int str_len) {
+        return std::string(static_cast<size_t>(str_len), 'x');
+      },
+      "xxx");
+  EXPECT_TRUE(matcher.Matches(3));
+  EXPECT_FALSE(matcher.Matches(1));
+}
+
+TEST(ResultOfTest, WorksForNonCopyableArguments) {
+  Matcher<std::unique_ptr<int>> matcher = ResultOf(
+      [](const std::unique_ptr<int>& str_len) {
+        return std::string(static_cast<size_t>(*str_len), 'x');
+      },
+      "xxx");
+  EXPECT_TRUE(matcher.Matches(std::unique_ptr<int>(new int(3))));
+  EXPECT_FALSE(matcher.Matches(std::unique_ptr<int>(new int(1))));
+}
+
+const int* ReferencingFunction(const int& n) { return &n; }
+
+struct ReferencingFunctor {
+  typedef const int* result_type;
+  result_type operator()(const int& n) { return &n; }
+};
+
+TEST(ResultOfTest, WorksForReferencingCallables) {
+  const int n = 1;
+  const int n2 = 1;
+  Matcher<const int&> matcher2 = ResultOf(ReferencingFunction, Eq(&n));
+  EXPECT_TRUE(matcher2.Matches(n));
+  EXPECT_FALSE(matcher2.Matches(n2));
+
+  Matcher<const int&> matcher3 = ResultOf(ReferencingFunctor(), Eq(&n));
+  EXPECT_TRUE(matcher3.Matches(n));
+  EXPECT_FALSE(matcher3.Matches(n2));
+}
+
+TEST(SizeIsTest, ImplementsSizeIs) {
+  vector<int> container;
+  EXPECT_THAT(container, SizeIs(0));
+  EXPECT_THAT(container, Not(SizeIs(1)));
+  container.push_back(0);
+  EXPECT_THAT(container, Not(SizeIs(0)));
+  EXPECT_THAT(container, SizeIs(1));
+  container.push_back(0);
+  EXPECT_THAT(container, Not(SizeIs(0)));
+  EXPECT_THAT(container, SizeIs(2));
+}
+
+TEST(SizeIsTest, WorksWithMap) {
+  map<std::string, int> container;
+  EXPECT_THAT(container, SizeIs(0));
+  EXPECT_THAT(container, Not(SizeIs(1)));
+  container.insert(make_pair("foo", 1));
+  EXPECT_THAT(container, Not(SizeIs(0)));
+  EXPECT_THAT(container, SizeIs(1));
+  container.insert(make_pair("bar", 2));
+  EXPECT_THAT(container, Not(SizeIs(0)));
+  EXPECT_THAT(container, SizeIs(2));
+}
+
+TEST(SizeIsTest, WorksWithReferences) {
+  vector<int> container;
+  Matcher<const vector<int>&> m = SizeIs(1);
+  EXPECT_THAT(container, Not(m));
+  container.push_back(0);
+  EXPECT_THAT(container, m);
+}
+
+TEST(SizeIsTest, WorksWithMoveOnly) {
+  ContainerHelper helper;
+  EXPECT_CALL(helper, Call(SizeIs(3)));
+  helper.Call(MakeUniquePtrs({1, 2, 3}));
+}
+
+// SizeIs should work for any type that provides a size() member function.
+// For example, a size_type member type should not need to be provided.
+struct MinimalistCustomType {
+  int size() const { return 1; }
+};
+TEST(SizeIsTest, WorksWithMinimalistCustomType) {
+  MinimalistCustomType container;
+  EXPECT_THAT(container, SizeIs(1));
+  EXPECT_THAT(container, Not(SizeIs(0)));
+}
+
+TEST(SizeIsTest, CanDescribeSelf) {
+  Matcher<vector<int>> m = SizeIs(2);
+  EXPECT_EQ("has a size that is equal to 2", Describe(m));
+  EXPECT_EQ("has a size that isn't equal to 2", DescribeNegation(m));
+}
+
+TEST(SizeIsTest, ExplainsResult) {
+  Matcher<vector<int>> m1 = SizeIs(2);
+  Matcher<vector<int>> m2 = SizeIs(Lt(2u));
+  Matcher<vector<int>> m3 = SizeIs(AnyOf(0, 3));
+  Matcher<vector<int>> m4 = SizeIs(Gt(1u));
+  vector<int> container;
+  EXPECT_EQ("whose size 0 doesn't match", Explain(m1, container));
+  EXPECT_EQ("whose size 0 matches", Explain(m2, container));
+  EXPECT_EQ("whose size 0 matches, which matches (is equal to 0)",
+            Explain(m3, container));
+  EXPECT_EQ("whose size 0 doesn't match", Explain(m4, container));
+  container.push_back(0);
+  container.push_back(0);
+  EXPECT_EQ("whose size 2 matches", Explain(m1, container));
+  EXPECT_EQ("whose size 2 doesn't match", Explain(m2, container));
+  EXPECT_EQ(
+      "whose size 2 doesn't match, isn't equal to 0, and isn't equal to 3",
+      Explain(m3, container));
+  EXPECT_EQ("whose size 2 matches", Explain(m4, container));
+}
+
+TEST(WhenSortedByTest, WorksForEmptyContainer) {
+  const vector<int> numbers;
+  EXPECT_THAT(numbers, WhenSortedBy(less<int>(), ElementsAre()));
+  EXPECT_THAT(numbers, Not(WhenSortedBy(less<int>(), ElementsAre(1))));
+}
+
+TEST(WhenSortedByTest, WorksForNonEmptyContainer) {
+  vector<unsigned> numbers;
+  numbers.push_back(3);
+  numbers.push_back(1);
+  numbers.push_back(2);
+  numbers.push_back(2);
+  EXPECT_THAT(numbers,
+              WhenSortedBy(greater<unsigned>(), ElementsAre(3, 2, 2, 1)));
+  EXPECT_THAT(numbers,
+              Not(WhenSortedBy(greater<unsigned>(), ElementsAre(1, 2, 2, 3))));
+}
+
+TEST(WhenSortedByTest, WorksForNonVectorContainer) {
+  list<std::string> words;
+  words.push_back("say");
+  words.push_back("hello");
+  words.push_back("world");
+  EXPECT_THAT(words, WhenSortedBy(less<std::string>(),
+                                  ElementsAre("hello", "say", "world")));
+  EXPECT_THAT(words, Not(WhenSortedBy(less<std::string>(),
+                                      ElementsAre("say", "hello", "world"))));
+}
+
+TEST(WhenSortedByTest, WorksForNativeArray) {
+  const int numbers[] = {1, 3, 2, 4};
+  const int sorted_numbers[] = {1, 2, 3, 4};
+  EXPECT_THAT(numbers, WhenSortedBy(less<int>(), ElementsAre(1, 2, 3, 4)));
+  EXPECT_THAT(numbers,
+              WhenSortedBy(less<int>(), ElementsAreArray(sorted_numbers)));
+  EXPECT_THAT(numbers, Not(WhenSortedBy(less<int>(), ElementsAre(1, 3, 2, 4))));
+}
+
+TEST(WhenSortedByTest, CanDescribeSelf) {
+  const Matcher<vector<int>> m = WhenSortedBy(less<int>(), ElementsAre(1, 2));
+  EXPECT_EQ(
+      "(when sorted) has 2 elements where\n"
+      "element #0 is equal to 1,\n"
+      "element #1 is equal to 2",
+      Describe(m));
+  EXPECT_EQ(
+      "(when sorted) doesn't have 2 elements, or\n"
+      "element #0 isn't equal to 1, or\n"
+      "element #1 isn't equal to 2",
+      DescribeNegation(m));
+}
+
+TEST(WhenSortedByTest, ExplainsMatchResult) {
+  const int a[] = {2, 1};
+  EXPECT_EQ(
+      Explain(WhenSortedBy(less<int>(), ElementsAre(2, 3)), a),
+      "which is { 1, 2 } when sorted, whose element #0 (1) isn't equal to 2");
+  EXPECT_EQ(Explain(WhenSortedBy(less<int>(), ElementsAre(1, 2)), a),
+            "which is { 1, 2 } when sorted");
+}
+
+// WhenSorted() is a simple wrapper on WhenSortedBy().  Hence we don't
+// need to test it as exhaustively as we test the latter.
+
+TEST(WhenSortedTest, WorksForEmptyContainer) {
+  const vector<int> numbers;
+  EXPECT_THAT(numbers, WhenSorted(ElementsAre()));
+  EXPECT_THAT(numbers, Not(WhenSorted(ElementsAre(1))));
+}
+
+TEST(WhenSortedTest, WorksForNonEmptyContainer) {
+  list<std::string> words;
+  words.push_back("3");
+  words.push_back("1");
+  words.push_back("2");
+  words.push_back("2");
+  EXPECT_THAT(words, WhenSorted(ElementsAre("1", "2", "2", "3")));
+  EXPECT_THAT(words, Not(WhenSorted(ElementsAre("3", "1", "2", "2"))));
+}
+
+TEST(WhenSortedTest, WorksForMapTypes) {
+  map<std::string, int> word_counts;
+  word_counts["and"] = 1;
+  word_counts["the"] = 1;
+  word_counts["buffalo"] = 2;
+  EXPECT_THAT(word_counts,
+              WhenSorted(ElementsAre(Pair("and", 1), Pair("buffalo", 2),
+                                     Pair("the", 1))));
+  EXPECT_THAT(word_counts,
+              Not(WhenSorted(ElementsAre(Pair("and", 1), Pair("the", 1),
+                                         Pair("buffalo", 2)))));
+}
+
+TEST(WhenSortedTest, WorksForMultiMapTypes) {
+  multimap<int, int> ifib;
+  ifib.insert(make_pair(8, 6));
+  ifib.insert(make_pair(2, 3));
+  ifib.insert(make_pair(1, 1));
+  ifib.insert(make_pair(3, 4));
+  ifib.insert(make_pair(1, 2));
+  ifib.insert(make_pair(5, 5));
+  EXPECT_THAT(ifib,
+              WhenSorted(ElementsAre(Pair(1, 1), Pair(1, 2), Pair(2, 3),
+                                     Pair(3, 4), Pair(5, 5), Pair(8, 6))));
+  EXPECT_THAT(ifib,
+              Not(WhenSorted(ElementsAre(Pair(8, 6), Pair(2, 3), Pair(1, 1),
+                                         Pair(3, 4), Pair(1, 2), Pair(5, 5)))));
+}
+
+TEST(WhenSortedTest, WorksForPolymorphicMatcher) {
+  std::deque<int> d;
+  d.push_back(2);
+  d.push_back(1);
+  EXPECT_THAT(d, WhenSorted(ElementsAre(1, 2)));
+  EXPECT_THAT(d, Not(WhenSorted(ElementsAre(2, 1))));
+}
+
+TEST(WhenSortedTest, WorksForVectorConstRefMatcher) {
+  std::deque<int> d;
+  d.push_back(2);
+  d.push_back(1);
+  Matcher<const std::vector<int>&> vector_match = ElementsAre(1, 2);
+  EXPECT_THAT(d, WhenSorted(vector_match));
+  Matcher<const std::vector<int>&> not_vector_match = ElementsAre(2, 1);
+  EXPECT_THAT(d, Not(WhenSorted(not_vector_match)));
+}
+
+// Deliberately bare pseudo-container.
+// Offers only begin() and end() accessors, yielding InputIterator.
+template <typename T>
+class Streamlike {
+ private:
+  class ConstIter;
+
+ public:
+  typedef ConstIter const_iterator;
+  typedef T value_type;
+
+  template <typename InIter>
+  Streamlike(InIter first, InIter last) : remainder_(first, last) {}
+
+  const_iterator begin() const {
+    return const_iterator(this, remainder_.begin());
+  }
+  const_iterator end() const { return const_iterator(this, remainder_.end()); }
+
+ private:
+  class ConstIter {
+   public:
+    using iterator_category = std::input_iterator_tag;
+    using value_type = T;
+    using difference_type = ptrdiff_t;
+    using pointer = const value_type*;
+    using reference = const value_type&;
+
+    ConstIter(const Streamlike* s, typename std::list<value_type>::iterator pos)
+        : s_(s), pos_(pos) {}
+
+    const value_type& operator*() const { return *pos_; }
+    const value_type* operator->() const { return &*pos_; }
+    ConstIter& operator++() {
+      s_->remainder_.erase(pos_++);
+      return *this;
+    }
+
+    // *iter++ is required to work (see std::istreambuf_iterator).
+    // (void)iter++ is also required to work.
+    class PostIncrProxy {
+     public:
+      explicit PostIncrProxy(const value_type& value) : value_(value) {}
+      value_type operator*() const { return value_; }
+
+     private:
+      value_type value_;
+    };
+    PostIncrProxy operator++(int) {
+      PostIncrProxy proxy(**this);
+      ++(*this);
+      return proxy;
+    }
+
+    friend bool operator==(const ConstIter& a, const ConstIter& b) {
+      return a.s_ == b.s_ && a.pos_ == b.pos_;
+    }
+    friend bool operator!=(const ConstIter& a, const ConstIter& b) {
+      return !(a == b);
+    }
+
+   private:
+    const Streamlike* s_;
+    typename std::list<value_type>::iterator pos_;
+  };
+
+  friend std::ostream& operator<<(std::ostream& os, const Streamlike& s) {
+    os << "[";
+    typedef typename std::list<value_type>::const_iterator Iter;
+    const char* sep = "";
+    for (Iter it = s.remainder_.begin(); it != s.remainder_.end(); ++it) {
+      os << sep << *it;
+      sep = ",";
+    }
+    os << "]";
+    return os;
+  }
+
+  mutable std::list<value_type> remainder_;  // modified by iteration
+};
+
+TEST(StreamlikeTest, Iteration) {
+  const int a[5] = {2, 1, 4, 5, 3};
+  Streamlike<int> s(a, a + 5);
+  Streamlike<int>::const_iterator it = s.begin();
+  const int* ip = a;
+  while (it != s.end()) {
+    SCOPED_TRACE(ip - a);
+    EXPECT_EQ(*ip++, *it++);
+  }
+}
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(BeginEndDistanceIsTest);
+
+TEST(BeginEndDistanceIsTest, WorksWithForwardList) {
+  std::forward_list<int> container;
+  EXPECT_THAT(container, BeginEndDistanceIs(0));
+  EXPECT_THAT(container, Not(BeginEndDistanceIs(1)));
+  container.push_front(0);
+  EXPECT_THAT(container, Not(BeginEndDistanceIs(0)));
+  EXPECT_THAT(container, BeginEndDistanceIs(1));
+  container.push_front(0);
+  EXPECT_THAT(container, Not(BeginEndDistanceIs(0)));
+  EXPECT_THAT(container, BeginEndDistanceIs(2));
+}
+
+TEST(BeginEndDistanceIsTest, WorksWithNonStdList) {
+  const int a[5] = {1, 2, 3, 4, 5};
+  Streamlike<int> s(a, a + 5);
+  EXPECT_THAT(s, BeginEndDistanceIs(5));
+}
+
+TEST(BeginEndDistanceIsTest, CanDescribeSelf) {
+  Matcher<vector<int>> m = BeginEndDistanceIs(2);
+  EXPECT_EQ("distance between begin() and end() is equal to 2", Describe(m));
+  EXPECT_EQ("distance between begin() and end() isn't equal to 2",
+            DescribeNegation(m));
+}
+
+TEST(BeginEndDistanceIsTest, WorksWithMoveOnly) {
+  ContainerHelper helper;
+  EXPECT_CALL(helper, Call(BeginEndDistanceIs(2)));
+  helper.Call(MakeUniquePtrs({1, 2}));
+}
+
+TEST_P(BeginEndDistanceIsTestP, ExplainsResult) {
+  Matcher<vector<int>> m1 = BeginEndDistanceIs(2);
+  Matcher<vector<int>> m2 = BeginEndDistanceIs(Lt(2));
+  Matcher<vector<int>> m3 = BeginEndDistanceIs(AnyOf(0, 3));
+  Matcher<vector<int>> m4 = BeginEndDistanceIs(GreaterThan(1));
+  vector<int> container;
+  EXPECT_EQ("whose distance between begin() and end() 0 doesn't match",
+            Explain(m1, container));
+  EXPECT_EQ("whose distance between begin() and end() 0 matches",
+            Explain(m2, container));
+  EXPECT_EQ(
+      "whose distance between begin() and end() 0 matches, which matches (is "
+      "equal to 0)",
+      Explain(m3, container));
+  EXPECT_EQ(
+      "whose distance between begin() and end() 0 doesn't match, which is 1 "
+      "less than 1",
+      Explain(m4, container));
+  container.push_back(0);
+  container.push_back(0);
+  EXPECT_EQ("whose distance between begin() and end() 2 matches",
+            Explain(m1, container));
+  EXPECT_EQ("whose distance between begin() and end() 2 doesn't match",
+            Explain(m2, container));
+  EXPECT_EQ(
+      "whose distance between begin() and end() 2 doesn't match, isn't equal "
+      "to 0, and isn't equal to 3",
+      Explain(m3, container));
+  EXPECT_EQ(
+      "whose distance between begin() and end() 2 matches, which is 1 more "
+      "than 1",
+      Explain(m4, container));
+}
+
+TEST(WhenSortedTest, WorksForStreamlike) {
+  // Streamlike 'container' provides only minimal iterator support.
+  // Its iterators are tagged with input_iterator_tag.
+  const int a[5] = {2, 1, 4, 5, 3};
+  Streamlike<int> s(std::begin(a), std::end(a));
+  EXPECT_THAT(s, WhenSorted(ElementsAre(1, 2, 3, 4, 5)));
+  EXPECT_THAT(s, Not(WhenSorted(ElementsAre(2, 1, 4, 5, 3))));
+}
+
+TEST(WhenSortedTest, WorksForVectorConstRefMatcherOnStreamlike) {
+  const int a[] = {2, 1, 4, 5, 3};
+  Streamlike<int> s(std::begin(a), std::end(a));
+  Matcher<const std::vector<int>&> vector_match = ElementsAre(1, 2, 3, 4, 5);
+  EXPECT_THAT(s, WhenSorted(vector_match));
+  EXPECT_THAT(s, Not(WhenSorted(ElementsAre(2, 1, 4, 5, 3))));
+}
+
+TEST(IsSupersetOfTest, WorksForNativeArray) {
+  const int subset[] = {1, 4};
+  const int superset[] = {1, 2, 4};
+  const int disjoint[] = {1, 0, 3};
+  EXPECT_THAT(subset, IsSupersetOf(subset));
+  EXPECT_THAT(subset, Not(IsSupersetOf(superset)));
+  EXPECT_THAT(superset, IsSupersetOf(subset));
+  EXPECT_THAT(subset, Not(IsSupersetOf(disjoint)));
+  EXPECT_THAT(disjoint, Not(IsSupersetOf(subset)));
+}
+
+TEST(IsSupersetOfTest, WorksWithDuplicates) {
+  const int not_enough[] = {1, 2};
+  const int enough[] = {1, 1, 2};
+  const int expected[] = {1, 1};
+  EXPECT_THAT(not_enough, Not(IsSupersetOf(expected)));
+  EXPECT_THAT(enough, IsSupersetOf(expected));
+}
+
+TEST(IsSupersetOfTest, WorksForEmpty) {
+  vector<int> numbers;
+  vector<int> expected;
+  EXPECT_THAT(numbers, IsSupersetOf(expected));
+  expected.push_back(1);
+  EXPECT_THAT(numbers, Not(IsSupersetOf(expected)));
+  expected.clear();
+  numbers.push_back(1);
+  numbers.push_back(2);
+  EXPECT_THAT(numbers, IsSupersetOf(expected));
+  expected.push_back(1);
+  EXPECT_THAT(numbers, IsSupersetOf(expected));
+  expected.push_back(2);
+  EXPECT_THAT(numbers, IsSupersetOf(expected));
+  expected.push_back(3);
+  EXPECT_THAT(numbers, Not(IsSupersetOf(expected)));
+}
+
+TEST(IsSupersetOfTest, WorksForStreamlike) {
+  const int a[5] = {1, 2, 3, 4, 5};
+  Streamlike<int> s(std::begin(a), std::end(a));
+
+  vector<int> expected;
+  expected.push_back(1);
+  expected.push_back(2);
+  expected.push_back(5);
+  EXPECT_THAT(s, IsSupersetOf(expected));
+
+  expected.push_back(0);
+  EXPECT_THAT(s, Not(IsSupersetOf(expected)));
+}
+
+TEST(IsSupersetOfTest, TakesStlContainer) {
+  const int actual[] = {3, 1, 2};
+
+  ::std::list<int> expected;
+  expected.push_back(1);
+  expected.push_back(3);
+  EXPECT_THAT(actual, IsSupersetOf(expected));
+
+  expected.push_back(4);
+  EXPECT_THAT(actual, Not(IsSupersetOf(expected)));
+}
+
+TEST(IsSupersetOfTest, Describe) {
+  typedef std::vector<int> IntVec;
+  IntVec expected;
+  expected.push_back(111);
+  expected.push_back(222);
+  expected.push_back(333);
+  EXPECT_THAT(
+      Describe<IntVec>(IsSupersetOf(expected)),
+      Eq("a surjection from elements to requirements exists such that:\n"
+         " - an element is equal to 111\n"
+         " - an element is equal to 222\n"
+         " - an element is equal to 333"));
+}
+
+TEST(IsSupersetOfTest, DescribeNegation) {
+  typedef std::vector<int> IntVec;
+  IntVec expected;
+  expected.push_back(111);
+  expected.push_back(222);
+  expected.push_back(333);
+  EXPECT_THAT(
+      DescribeNegation<IntVec>(IsSupersetOf(expected)),
+      Eq("no surjection from elements to requirements exists such that:\n"
+         " - an element is equal to 111\n"
+         " - an element is equal to 222\n"
+         " - an element is equal to 333"));
+}
+
+TEST(IsSupersetOfTest, MatchAndExplain) {
+  std::vector<int> v;
+  v.push_back(2);
+  v.push_back(3);
+  std::vector<int> expected;
+  expected.push_back(1);
+  expected.push_back(2);
+  StringMatchResultListener listener;
+  ASSERT_FALSE(ExplainMatchResult(IsSupersetOf(expected), v, &listener))
+      << listener.str();
+  EXPECT_THAT(listener.str(),
+              Eq("where the following matchers don't match any elements:\n"
+                 "matcher #0: is equal to 1"));
+
+  v.push_back(1);
+  listener.Clear();
+  ASSERT_TRUE(ExplainMatchResult(IsSupersetOf(expected), v, &listener))
+      << listener.str();
+  EXPECT_THAT(listener.str(), Eq("where:\n"
+                                 " - element #0 is matched by matcher #1,\n"
+                                 " - element #2 is matched by matcher #0"));
+}
+
+TEST(IsSupersetOfTest, WorksForRhsInitializerList) {
+  const int numbers[] = {1, 3, 6, 2, 4, 5};
+  EXPECT_THAT(numbers, IsSupersetOf({1, 2}));
+  EXPECT_THAT(numbers, Not(IsSupersetOf({3, 0})));
+}
+
+TEST(IsSupersetOfTest, WorksWithMoveOnly) {
+  ContainerHelper helper;
+  EXPECT_CALL(helper, Call(IsSupersetOf({Pointee(1)})));
+  helper.Call(MakeUniquePtrs({1, 2}));
+  EXPECT_CALL(helper, Call(Not(IsSupersetOf({Pointee(1), Pointee(2)}))));
+  helper.Call(MakeUniquePtrs({2}));
+}
+
+TEST(IsSubsetOfTest, WorksForNativeArray) {
+  const int subset[] = {1, 4};
+  const int superset[] = {1, 2, 4};
+  const int disjoint[] = {1, 0, 3};
+  EXPECT_THAT(subset, IsSubsetOf(subset));
+  EXPECT_THAT(subset, IsSubsetOf(superset));
+  EXPECT_THAT(superset, Not(IsSubsetOf(subset)));
+  EXPECT_THAT(subset, Not(IsSubsetOf(disjoint)));
+  EXPECT_THAT(disjoint, Not(IsSubsetOf(subset)));
+}
+
+TEST(IsSubsetOfTest, WorksWithDuplicates) {
+  const int not_enough[] = {1, 2};
+  const int enough[] = {1, 1, 2};
+  const int actual[] = {1, 1};
+  EXPECT_THAT(actual, Not(IsSubsetOf(not_enough)));
+  EXPECT_THAT(actual, IsSubsetOf(enough));
+}
+
+TEST(IsSubsetOfTest, WorksForEmpty) {
+  vector<int> numbers;
+  vector<int> expected;
+  EXPECT_THAT(numbers, IsSubsetOf(expected));
+  expected.push_back(1);
+  EXPECT_THAT(numbers, IsSubsetOf(expected));
+  expected.clear();
+  numbers.push_back(1);
+  numbers.push_back(2);
+  EXPECT_THAT(numbers, Not(IsSubsetOf(expected)));
+  expected.push_back(1);
+  EXPECT_THAT(numbers, Not(IsSubsetOf(expected)));
+  expected.push_back(2);
+  EXPECT_THAT(numbers, IsSubsetOf(expected));
+  expected.push_back(3);
+  EXPECT_THAT(numbers, IsSubsetOf(expected));
+}
+
+TEST(IsSubsetOfTest, WorksForStreamlike) {
+  const int a[5] = {1, 2};
+  Streamlike<int> s(std::begin(a), std::end(a));
+
+  vector<int> expected;
+  expected.push_back(1);
+  EXPECT_THAT(s, Not(IsSubsetOf(expected)));
+  expected.push_back(2);
+  expected.push_back(5);
+  EXPECT_THAT(s, IsSubsetOf(expected));
+}
+
+TEST(IsSubsetOfTest, TakesStlContainer) {
+  const int actual[] = {3, 1, 2};
+
+  ::std::list<int> expected;
+  expected.push_back(1);
+  expected.push_back(3);
+  EXPECT_THAT(actual, Not(IsSubsetOf(expected)));
+
+  expected.push_back(2);
+  expected.push_back(4);
+  EXPECT_THAT(actual, IsSubsetOf(expected));
+}
+
+TEST(IsSubsetOfTest, Describe) {
+  typedef std::vector<int> IntVec;
+  IntVec expected;
+  expected.push_back(111);
+  expected.push_back(222);
+  expected.push_back(333);
+
+  EXPECT_THAT(
+      Describe<IntVec>(IsSubsetOf(expected)),
+      Eq("an injection from elements to requirements exists such that:\n"
+         " - an element is equal to 111\n"
+         " - an element is equal to 222\n"
+         " - an element is equal to 333"));
+}
+
+TEST(IsSubsetOfTest, DescribeNegation) {
+  typedef std::vector<int> IntVec;
+  IntVec expected;
+  expected.push_back(111);
+  expected.push_back(222);
+  expected.push_back(333);
+  EXPECT_THAT(
+      DescribeNegation<IntVec>(IsSubsetOf(expected)),
+      Eq("no injection from elements to requirements exists such that:\n"
+         " - an element is equal to 111\n"
+         " - an element is equal to 222\n"
+         " - an element is equal to 333"));
+}
+
+TEST(IsSubsetOfTest, MatchAndExplain) {
+  std::vector<int> v;
+  v.push_back(2);
+  v.push_back(3);
+  std::vector<int> expected;
+  expected.push_back(1);
+  expected.push_back(2);
+  StringMatchResultListener listener;
+  ASSERT_FALSE(ExplainMatchResult(IsSubsetOf(expected), v, &listener))
+      << listener.str();
+  EXPECT_THAT(listener.str(),
+              Eq("where the following elements don't match any matchers:\n"
+                 "element #1: 3"));
+
+  expected.push_back(3);
+  listener.Clear();
+  ASSERT_TRUE(ExplainMatchResult(IsSubsetOf(expected), v, &listener))
+      << listener.str();
+  EXPECT_THAT(listener.str(), Eq("where:\n"
+                                 " - element #0 is matched by matcher #1,\n"
+                                 " - element #1 is matched by matcher #2"));
+}
+
+TEST(IsSubsetOfTest, WorksForRhsInitializerList) {
+  const int numbers[] = {1, 2, 3};
+  EXPECT_THAT(numbers, IsSubsetOf({1, 2, 3, 4}));
+  EXPECT_THAT(numbers, Not(IsSubsetOf({1, 2})));
+}
+
+TEST(IsSubsetOfTest, WorksWithMoveOnly) {
+  ContainerHelper helper;
+  EXPECT_CALL(helper, Call(IsSubsetOf({Pointee(1), Pointee(2)})));
+  helper.Call(MakeUniquePtrs({1}));
+  EXPECT_CALL(helper, Call(Not(IsSubsetOf({Pointee(1)}))));
+  helper.Call(MakeUniquePtrs({2}));
+}
+
+// A container whose iterator returns a temporary. This can iterate over the
+// characters in a string.
+class CharString {
+ public:
+  using value_type = char;
+
+  class const_iterator {
+   public:
+    using iterator_category = std::input_iterator_tag;
+    using value_type = char;
+    using difference_type = std::ptrdiff_t;
+    using pointer = const char*;
+    using reference = const char&;
+
+    // Create an iterator that points to the given character.
+    explicit const_iterator(const char* ptr) : ptr_(ptr) {}
+
+    // Returns the current character. IMPORTANT: this must return a temporary,
+    // not a reference, to test that ElementsAre() works with containers whose
+    // iterators return temporaries.
+    char operator*() const { return *ptr_; }
+
+    // Advances to the next character.
+    const_iterator& operator++() {
+      ++ptr_;
+      return *this;
+    }
+
+    // Compares two iterators.
+    bool operator==(const const_iterator& other) const {
+      return ptr_ == other.ptr_;
+    }
+    bool operator!=(const const_iterator& other) const {
+      return ptr_ != other.ptr_;
+    }
+
+   private:
+    const char* ptr_ = nullptr;
+  };
+
+  // Creates a CharString that contains the given string.
+  explicit CharString(const std::string& s) : s_(s) {}
+
+  // Returns an iterator pointing to the first character in the string.
+  const_iterator begin() const { return const_iterator(s_.c_str()); }
+
+  // Returns an iterator pointing past the last character in the string.
+  const_iterator end() const { return const_iterator(s_.c_str() + s_.size()); }
+
+ private:
+  std::string s_;
+};
+
+// Tests using ElementsAre() with a container whose iterator returns a
+// temporary.
+TEST(ElementsAreTest, WorksWithContainerThatReturnsTempInIterator) {
+  CharString s("abc");
+  EXPECT_THAT(s, ElementsAre('a', 'b', 'c'));
+  EXPECT_THAT(s, Not(ElementsAre('a', 'b', 'd')));
+}
+
+// Tests using ElementsAreArray() with a container whose iterator returns a
+// temporary.
+TEST(ElementsAreArrayTest, WorksWithContainerThatReturnsTempInIterator) {
+  CharString s("abc");
+  EXPECT_THAT(s, ElementsAreArray({'a', 'b', 'c'}));
+  EXPECT_THAT(s, Not(ElementsAreArray({'a', 'b', 'd'})));
+}
+
+// A container whose iterator returns a temporary and is not copy-assignable.
+// This simulates the behavior of the proxy object returned by absl::StrSplit().
+class CharString2 {
+ public:
+  using value_type = char;
+
+  class const_iterator {
+   public:
+    using iterator_category = std::input_iterator_tag;
+    using value_type = char;
+    using difference_type = std::ptrdiff_t;
+    using pointer = const char*;
+    using reference = const char&;
+
+    // Make const_iterator copy-constructible but not copy-assignable,
+    // simulating the behavior of the proxy object returned by absl::StrSplit().
+    const_iterator(const const_iterator&) = default;
+    const_iterator& operator=(const const_iterator&) = delete;
+
+    // Create an iterator that points to the given character.
+    explicit const_iterator(const char* ptr) : ptr_(ptr) {}
+
+    // Returns the current character. IMPORTANT: this must return a temporary,
+    // not a reference, to test that ElementsAre() works with containers whose
+    // iterators return temporaries.
+    char operator*() const { return *ptr_; }
+
+    // Advances to the next character.
+    const_iterator& operator++() {
+      ++ptr_;
+      return *this;
+    }
+
+    // Compares two iterators.
+    bool operator==(const const_iterator& other) const {
+      return ptr_ == other.ptr_;
+    }
+    bool operator!=(const const_iterator& other) const {
+      return ptr_ != other.ptr_;
+    }
+
+   private:
+    const char* ptr_ = nullptr;
+  };
+
+  // Creates a CharString that contains the given string.
+  explicit CharString2(const std::string& s) : s_(s) {}
+
+  // Returns an iterator pointing to the first character in the string.
+  const_iterator begin() const { return const_iterator(s_.c_str()); }
+
+  // Returns an iterator pointing past the last character in the string.
+  const_iterator end() const { return const_iterator(s_.c_str() + s_.size()); }
+
+ private:
+  std::string s_;
+};
+
+// Tests using ElementsAre() with a container whose iterator returns a
+// temporary and is not copy-assignable.
+TEST(ElementsAreTest, WorksWithContainerThatReturnsTempInUnassignableIterator) {
+  CharString2 s("abc");
+  EXPECT_THAT(s, ElementsAre('a', 'b', 'c'));
+  EXPECT_THAT(s, Not(ElementsAre('a', 'b', 'd')));
+}
+
+// Tests using ElementsAreArray() with a container whose iterator returns a
+// temporary and is not copy-assignable.
+TEST(ElementsAreArrayTest,
+     WorksWithContainerThatReturnsTempInUnassignableIterator) {
+  CharString2 s("abc");
+  EXPECT_THAT(s, ElementsAreArray({'a', 'b', 'c'}));
+  EXPECT_THAT(s, Not(ElementsAreArray({'a', 'b', 'd'})));
+}
+
+// A container whose iterator returns a temporary and is neither
+// copy-constructible nor copy-assignable.
+class CharString3 {
+ public:
+  using value_type = char;
+
+  class const_iterator {
+   public:
+    using iterator_category = std::input_iterator_tag;
+    using value_type = char;
+    using difference_type = std::ptrdiff_t;
+    using pointer = const char*;
+    using reference = const char&;
+
+    // Make const_iterator neither copy-constructible nor copy-assignable.
+    const_iterator(const const_iterator&) = delete;
+    const_iterator& operator=(const const_iterator&) = delete;
+
+    // Create an iterator that points to the given character.
+    explicit const_iterator(const char* ptr) : ptr_(ptr) {}
+
+    // Returns the current character. IMPORTANT: this must return a temporary,
+    // not a reference, to test that ElementsAre() works with containers whose
+    // iterators return temporaries.
+    char operator*() const { return *ptr_; }
+
+    // Advances to the next character.
+    const_iterator& operator++() {
+      ++ptr_;
+      return *this;
+    }
+
+    // Compares two iterators.
+    bool operator==(const const_iterator& other) const {
+      return ptr_ == other.ptr_;
+    }
+    bool operator!=(const const_iterator& other) const {
+      return ptr_ != other.ptr_;
+    }
+
+   private:
+    const char* ptr_ = nullptr;
+  };
+
+  // Creates a CharString that contains the given string.
+  explicit CharString3(const std::string& s) : s_(s) {}
+
+  // Returns an iterator pointing to the first character in the string.
+  const_iterator begin() const { return const_iterator(s_.c_str()); }
+
+  // Returns an iterator pointing past the last character in the string.
+  const_iterator end() const { return const_iterator(s_.c_str() + s_.size()); }
+
+ private:
+  std::string s_;
+};
+
+// Tests using ElementsAre() with a container whose iterator returns a
+// temporary and is neither copy-constructible nor copy-assignable.
+TEST(ElementsAreTest, WorksWithContainerThatReturnsTempInUncopyableIterator) {
+  CharString3 s("abc");
+  EXPECT_THAT(s, ElementsAre('a', 'b', 'c'));
+  EXPECT_THAT(s, Not(ElementsAre('a', 'b', 'd')));
+}
+
+// Tests using ElementsAreArray() with a container whose iterator returns a
+// temporary and is neither copy-constructible nor copy-assignable.
+TEST(ElementsAreArrayTest,
+     WorksWithContainerThatReturnsTempInUncopyableIterator) {
+  CharString3 s("abc");
+  EXPECT_THAT(s, ElementsAreArray({'a', 'b', 'c'}));
+  EXPECT_THAT(s, Not(ElementsAreArray({'a', 'b', 'd'})));
+}
+
+// A container whose iterator returns a temporary, is neither
+// copy-constructible nor copy-assignable, and has no member types.
+class CharString4 {
+ public:
+  using value_type = char;
+
+  class const_iterator {
+   public:
+    // Do not define difference_type, etc.
+
+    // Make const_iterator neither copy-constructible nor copy-assignable.
+    const_iterator(const const_iterator&) = delete;
+    const_iterator& operator=(const const_iterator&) = delete;
+
+    // Create an iterator that points to the given character.
+    explicit const_iterator(const char* ptr) : ptr_(ptr) {}
+
+    // Returns the current character. IMPORTANT: this must return a temporary,
+    // not a reference, to test that ElementsAre() works with containers whose
+    // iterators return temporaries.
+    char operator*() const { return *ptr_; }
+
+    // Advances to the next character.
+    const_iterator& operator++() {
+      ++ptr_;
+      return *this;
+    }
+
+    // Compares two iterators.
+    bool operator==(const const_iterator& other) const {
+      return ptr_ == other.ptr_;
+    }
+    bool operator!=(const const_iterator& other) const {
+      return ptr_ != other.ptr_;
+    }
+
+   private:
+    const char* ptr_ = nullptr;
+  };
+
+  // Creates a CharString that contains the given string.
+  explicit CharString4(const std::string& s) : s_(s) {}
+
+  // Returns an iterator pointing to the first character in the string.
+  const_iterator begin() const { return const_iterator(s_.c_str()); }
+
+  // Returns an iterator pointing past the last character in the string.
+  const_iterator end() const { return const_iterator(s_.c_str() + s_.size()); }
+
+ private:
+  std::string s_;
+};
+
+// Tests using ElementsAre() with a container whose iterator returns a
+// temporary, is neither copy-constructible nor copy-assignable, and has no
+// member types.
+TEST(ElementsAreTest, WorksWithContainerWithIteratorWithNoMemberTypes) {
+  CharString4 s("abc");
+  EXPECT_THAT(s, ElementsAre('a', 'b', 'c'));
+  EXPECT_THAT(s, Not(ElementsAre('a', 'b', 'd')));
+}
+
+// Tests using ElementsAreArray() with a container whose iterator returns a
+// temporary, is neither copy-constructible nor copy-assignable, and has no
+// member types.
+TEST(ElementsAreArrayTest, WorksWithContainerWithIteratorWithNoMemberTypes) {
+  CharString4 s("abc");
+  EXPECT_THAT(s, ElementsAreArray({'a', 'b', 'c'}));
+  EXPECT_THAT(s, Not(ElementsAreArray({'a', 'b', 'd'})));
+}
+
+// Tests using ElementsAre() and ElementsAreArray() with stream-like
+// "containers".
+
+TEST(ElemensAreStreamTest, WorksForStreamlike) {
+  const int a[5] = {1, 2, 3, 4, 5};
+  Streamlike<int> s(std::begin(a), std::end(a));
+  EXPECT_THAT(s, ElementsAre(1, 2, 3, 4, 5));
+  EXPECT_THAT(s, Not(ElementsAre(2, 1, 4, 5, 3)));
+}
+
+TEST(ElemensAreArrayStreamTest, WorksForStreamlike) {
+  const int a[5] = {1, 2, 3, 4, 5};
+  Streamlike<int> s(std::begin(a), std::end(a));
+
+  vector<int> expected;
+  expected.push_back(1);
+  expected.push_back(2);
+  expected.push_back(3);
+  expected.push_back(4);
+  expected.push_back(5);
+  EXPECT_THAT(s, ElementsAreArray(expected));
+
+  expected[3] = 0;
+  EXPECT_THAT(s, Not(ElementsAreArray(expected)));
+}
+
+TEST(ElementsAreTest, WorksWithUncopyable) {
+  Uncopyable objs[2];
+  objs[0].set_value(-3);
+  objs[1].set_value(1);
+  EXPECT_THAT(objs, ElementsAre(UncopyableIs(-3), Truly(ValueIsPositive)));
+}
+
+TEST(ElementsAreTest, WorksWithMoveOnly) {
+  ContainerHelper helper;
+  EXPECT_CALL(helper, Call(ElementsAre(Pointee(1), Pointee(2))));
+  helper.Call(MakeUniquePtrs({1, 2}));
+
+  EXPECT_CALL(helper, Call(ElementsAreArray({Pointee(3), Pointee(4)})));
+  helper.Call(MakeUniquePtrs({3, 4}));
+}
+
+TEST(ElementsAreTest, TakesStlContainer) {
+  const int actual[] = {3, 1, 2};
+
+  ::std::list<int> expected;
+  expected.push_back(3);
+  expected.push_back(1);
+  expected.push_back(2);
+  EXPECT_THAT(actual, ElementsAreArray(expected));
+
+  expected.push_back(4);
+  EXPECT_THAT(actual, Not(ElementsAreArray(expected)));
+}
+
+// Tests for UnorderedElementsAreArray()
+
+TEST(UnorderedElementsAreArrayTest, SucceedsWhenExpected) {
+  const int a[] = {0, 1, 2, 3, 4};
+  std::vector<int> s(std::begin(a), std::end(a));
+  do {
+    StringMatchResultListener listener;
+    EXPECT_TRUE(ExplainMatchResult(UnorderedElementsAreArray(a), s, &listener))
+        << listener.str();
+  } while (std::next_permutation(s.begin(), s.end()));
+}
+
+TEST(UnorderedElementsAreArrayTest, VectorBool) {
+  const bool a[] = {false, true, false, true, true};
+  const bool b[] = {true, false, true, true, false};
+  std::vector<bool> expected(std::begin(a), std::end(a));
+  std::vector<bool> actual(std::begin(b), std::end(b));
+  StringMatchResultListener listener;
+  EXPECT_TRUE(ExplainMatchResult(UnorderedElementsAreArray(expected), actual,
+                                 &listener))
+      << listener.str();
+}
+
+TEST(UnorderedElementsAreArrayTest, WorksForStreamlike) {
+  // Streamlike 'container' provides only minimal iterator support.
+  // Its iterators are tagged with input_iterator_tag, and it has no
+  // size() or empty() methods.
+  const int a[5] = {2, 1, 4, 5, 3};
+  Streamlike<int> s(std::begin(a), std::end(a));
+
+  ::std::vector<int> expected;
+  expected.push_back(1);
+  expected.push_back(2);
+  expected.push_back(3);
+  expected.push_back(4);
+  expected.push_back(5);
+  EXPECT_THAT(s, UnorderedElementsAreArray(expected));
+
+  expected.push_back(6);
+  EXPECT_THAT(s, Not(UnorderedElementsAreArray(expected)));
+}
+
+TEST(UnorderedElementsAreArrayTest, TakesStlContainer) {
+  const int actual[] = {3, 1, 2};
+
+  ::std::list<int> expected;
+  expected.push_back(1);
+  expected.push_back(2);
+  expected.push_back(3);
+  EXPECT_THAT(actual, UnorderedElementsAreArray(expected));
+
+  expected.push_back(4);
+  EXPECT_THAT(actual, Not(UnorderedElementsAreArray(expected)));
+}
+
+TEST(UnorderedElementsAreArrayTest, TakesInitializerList) {
+  const int a[5] = {2, 1, 4, 5, 3};
+  EXPECT_THAT(a, UnorderedElementsAreArray({1, 2, 3, 4, 5}));
+  EXPECT_THAT(a, Not(UnorderedElementsAreArray({1, 2, 3, 4, 6})));
+}
+
+TEST(UnorderedElementsAreArrayTest, TakesInitializerListOfCStrings) {
+  const std::string a[5] = {"a", "b", "c", "d", "e"};
+  EXPECT_THAT(a, UnorderedElementsAreArray({"a", "b", "c", "d", "e"}));
+  EXPECT_THAT(a, Not(UnorderedElementsAreArray({"a", "b", "c", "d", "ef"})));
+}
+
+TEST(UnorderedElementsAreArrayTest, TakesInitializerListOfSameTypedMatchers) {
+  const int a[5] = {2, 1, 4, 5, 3};
+  EXPECT_THAT(a,
+              UnorderedElementsAreArray({Eq(1), Eq(2), Eq(3), Eq(4), Eq(5)}));
+  EXPECT_THAT(
+      a, Not(UnorderedElementsAreArray({Eq(1), Eq(2), Eq(3), Eq(4), Eq(6)})));
+}
+
+TEST(UnorderedElementsAreArrayTest,
+     TakesInitializerListOfDifferentTypedMatchers) {
+  const int a[5] = {2, 1, 4, 5, 3};
+  // The compiler cannot infer the type of the initializer list if its
+  // elements have different types.  We must explicitly specify the
+  // unified element type in this case.
+  EXPECT_THAT(a, UnorderedElementsAreArray<Matcher<int>>(
+                     {Eq(1), Ne(-2), Ge(3), Le(4), Eq(5)}));
+  EXPECT_THAT(a, Not(UnorderedElementsAreArray<Matcher<int>>(
+                     {Eq(1), Ne(-2), Ge(3), Le(4), Eq(6)})));
+}
+
+TEST(UnorderedElementsAreArrayTest, WorksWithMoveOnly) {
+  ContainerHelper helper;
+  EXPECT_CALL(helper,
+              Call(UnorderedElementsAreArray({Pointee(1), Pointee(2)})));
+  helper.Call(MakeUniquePtrs({2, 1}));
+}
+
+class UnorderedElementsAreTest : public testing::Test {
+ protected:
+  typedef std::vector<int> IntVec;
+};
+
+TEST_F(UnorderedElementsAreTest, WorksWithUncopyable) {
+  Uncopyable objs[2];
+  objs[0].set_value(-3);
+  objs[1].set_value(1);
+  EXPECT_THAT(objs,
+              UnorderedElementsAre(Truly(ValueIsPositive), UncopyableIs(-3)));
+}
+
+TEST_F(UnorderedElementsAreTest, SucceedsWhenExpected) {
+  const int a[] = {1, 2, 3};
+  std::vector<int> s(std::begin(a), std::end(a));
+  do {
+    StringMatchResultListener listener;
+    EXPECT_TRUE(ExplainMatchResult(UnorderedElementsAre(1, 2, 3), s, &listener))
+        << listener.str();
+  } while (std::next_permutation(s.begin(), s.end()));
+}
+
+TEST_F(UnorderedElementsAreTest, FailsWhenAnElementMatchesNoMatcher) {
+  const int a[] = {1, 2, 3};
+  std::vector<int> s(std::begin(a), std::end(a));
+  std::vector<Matcher<int>> mv;
+  mv.push_back(1);
+  mv.push_back(2);
+  mv.push_back(2);
+  // The element with value '3' matches nothing: fail fast.
+  StringMatchResultListener listener;
+  EXPECT_FALSE(ExplainMatchResult(UnorderedElementsAreArray(mv), s, &listener))
+      << listener.str();
+}
+
+TEST_F(UnorderedElementsAreTest, WorksForStreamlike) {
+  // Streamlike 'container' provides only minimal iterator support.
+  // Its iterators are tagged with input_iterator_tag, and it has no
+  // size() or empty() methods.
+  const int a[5] = {2, 1, 4, 5, 3};
+  Streamlike<int> s(std::begin(a), std::end(a));
+
+  EXPECT_THAT(s, UnorderedElementsAre(1, 2, 3, 4, 5));
+  EXPECT_THAT(s, Not(UnorderedElementsAre(2, 2, 3, 4, 5)));
+}
+
+TEST_F(UnorderedElementsAreTest, WorksWithMoveOnly) {
+  ContainerHelper helper;
+  EXPECT_CALL(helper, Call(UnorderedElementsAre(Pointee(1), Pointee(2))));
+  helper.Call(MakeUniquePtrs({2, 1}));
+}
+
+// One naive implementation of the matcher runs in O(N!) time, which is too
+// slow for many real-world inputs. This test shows that our matcher can match
+// 100 inputs very quickly (a few milliseconds).  An O(100!) is 10^158
+// iterations and obviously effectively incomputable.
+// [ RUN      ] UnorderedElementsAreTest.Performance
+// [       OK ] UnorderedElementsAreTest.Performance (4 ms)
+TEST_F(UnorderedElementsAreTest, Performance) {
+  std::vector<int> s;
+  std::vector<Matcher<int>> mv;
+  for (int i = 0; i < 100; ++i) {
+    s.push_back(i);
+    mv.push_back(_);
+  }
+  mv[50] = Eq(0);
+  StringMatchResultListener listener;
+  EXPECT_TRUE(ExplainMatchResult(UnorderedElementsAreArray(mv), s, &listener))
+      << listener.str();
+}
+
+// Another variant of 'Performance' with similar expectations.
+// [ RUN      ] UnorderedElementsAreTest.PerformanceHalfStrict
+// [       OK ] UnorderedElementsAreTest.PerformanceHalfStrict (4 ms)
+TEST_F(UnorderedElementsAreTest, PerformanceHalfStrict) {
+  std::vector<int> s;
+  std::vector<Matcher<int>> mv;
+  for (int i = 0; i < 100; ++i) {
+    s.push_back(i);
+    if (i & 1) {
+      mv.push_back(_);
+    } else {
+      mv.push_back(i);
+    }
+  }
+  StringMatchResultListener listener;
+  EXPECT_TRUE(ExplainMatchResult(UnorderedElementsAreArray(mv), s, &listener))
+      << listener.str();
+}
+
+TEST_F(UnorderedElementsAreTest, FailMessageCountWrong) {
+  std::vector<int> v;
+  v.push_back(4);
+  StringMatchResultListener listener;
+  EXPECT_FALSE(ExplainMatchResult(UnorderedElementsAre(1, 2, 3), v, &listener))
+      << listener.str();
+  EXPECT_THAT(listener.str(),
+              Eq("which has 1 element\n"
+                 "where the following matchers don't match any elements:\n"
+                 "matcher #0: is equal to 1,\n"
+                 "matcher #1: is equal to 2,\n"
+                 "matcher #2: is equal to 3\n"
+                 "and where the following elements don't match any matchers:\n"
+                 "element #0: 4"));
+}
+
+TEST_F(UnorderedElementsAreTest, FailMessageCountWrongZero) {
+  std::vector<int> v;
+  StringMatchResultListener listener;
+  EXPECT_FALSE(ExplainMatchResult(UnorderedElementsAre(1, 2, 3), v, &listener))
+      << listener.str();
+  EXPECT_THAT(listener.str(),
+              Eq("where the following matchers don't match any elements:\n"
+                 "matcher #0: is equal to 1,\n"
+                 "matcher #1: is equal to 2,\n"
+                 "matcher #2: is equal to 3"));
+}
+
+TEST_F(UnorderedElementsAreTest, FailMessageUnmatchedMatchers) {
+  std::vector<int> v;
+  v.push_back(1);
+  v.push_back(1);
+  StringMatchResultListener listener;
+  EXPECT_FALSE(ExplainMatchResult(UnorderedElementsAre(1, 2), v, &listener))
+      << listener.str();
+  EXPECT_THAT(listener.str(),
+              Eq("where the following matchers don't match any elements:\n"
+                 "matcher #1: is equal to 2"));
+}
+
+TEST_F(UnorderedElementsAreTest, FailMessageUnmatchedElements) {
+  std::vector<int> v;
+  v.push_back(1);
+  v.push_back(2);
+  StringMatchResultListener listener;
+  EXPECT_FALSE(ExplainMatchResult(UnorderedElementsAre(1, 1), v, &listener))
+      << listener.str();
+  EXPECT_THAT(listener.str(),
+              Eq("where the following elements don't match any matchers:\n"
+                 "element #1: 2"));
+}
+
+TEST_F(UnorderedElementsAreTest, FailMessageUnmatchedMatcherAndElement) {
+  std::vector<int> v;
+  v.push_back(2);
+  v.push_back(3);
+  StringMatchResultListener listener;
+  EXPECT_FALSE(ExplainMatchResult(UnorderedElementsAre(1, 2), v, &listener))
+      << listener.str();
+  EXPECT_THAT(listener.str(),
+              Eq("where"
+                 " the following matchers don't match any elements:\n"
+                 "matcher #0: is equal to 1\n"
+                 "and"
+                 " where"
+                 " the following elements don't match any matchers:\n"
+                 "element #1: 3"));
+}
+
+// Test helper for formatting element, matcher index pairs in expectations.
+static std::string EMString(int element, int matcher) {
+  stringstream ss;
+  ss << "(element #" << element << ", matcher #" << matcher << ")";
+  return ss.str();
+}
+
+TEST_F(UnorderedElementsAreTest, FailMessageImperfectMatchOnly) {
+  // A situation where all elements and matchers have a match
+  // associated with them, but the max matching is not perfect.
+  std::vector<std::string> v;
+  v.push_back("a");
+  v.push_back("b");
+  v.push_back("c");
+  StringMatchResultListener listener;
+  EXPECT_FALSE(ExplainMatchResult(
+      UnorderedElementsAre("a", "a", AnyOf("b", "c")), v, &listener))
+      << listener.str();
+
+  std::string prefix =
+      "where no permutation of the elements can satisfy all matchers, "
+      "and the closest match is 2 of 3 matchers with the "
+      "pairings:\n";
+
+  // We have to be a bit loose here, because there are 4 valid max matches.
+  EXPECT_THAT(
+      listener.str(),
+      AnyOf(
+          prefix + "{\n  " + EMString(0, 0) + ",\n  " + EMString(1, 2) + "\n}",
+          prefix + "{\n  " + EMString(0, 1) + ",\n  " + EMString(1, 2) + "\n}",
+          prefix + "{\n  " + EMString(0, 0) + ",\n  " + EMString(2, 2) + "\n}",
+          prefix + "{\n  " + EMString(0, 1) + ",\n  " + EMString(2, 2) +
+              "\n}"));
+}
+
+TEST_F(UnorderedElementsAreTest, Describe) {
+  EXPECT_THAT(Describe<IntVec>(UnorderedElementsAre()), Eq("is empty"));
+  EXPECT_THAT(Describe<IntVec>(UnorderedElementsAre(345)),
+              Eq("has 1 element and that element is equal to 345"));
+  EXPECT_THAT(Describe<IntVec>(UnorderedElementsAre(111, 222, 333)),
+              Eq("has 3 elements and there exists some permutation "
+                 "of elements such that:\n"
+                 " - element #0 is equal to 111, and\n"
+                 " - element #1 is equal to 222, and\n"
+                 " - element #2 is equal to 333"));
+}
+
+TEST_F(UnorderedElementsAreTest, DescribeNegation) {
+  EXPECT_THAT(DescribeNegation<IntVec>(UnorderedElementsAre()),
+              Eq("isn't empty"));
+  EXPECT_THAT(
+      DescribeNegation<IntVec>(UnorderedElementsAre(345)),
+      Eq("doesn't have 1 element, or has 1 element that isn't equal to 345"));
+  EXPECT_THAT(DescribeNegation<IntVec>(UnorderedElementsAre(123, 234, 345)),
+              Eq("doesn't have 3 elements, or there exists no permutation "
+                 "of elements such that:\n"
+                 " - element #0 is equal to 123, and\n"
+                 " - element #1 is equal to 234, and\n"
+                 " - element #2 is equal to 345"));
+}
+
+// Tests Each().
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(EachTest);
+
+TEST_P(EachTestP, ExplainsMatchResultCorrectly) {
+  set<int> a;  // empty
+
+  Matcher<set<int>> m = Each(2);
+  EXPECT_EQ("", Explain(m, a));
+
+  Matcher<const int (&)[1]> n = Each(1);  // NOLINT
+
+  const int b[1] = {1};
+  EXPECT_EQ("", Explain(n, b));
+
+  n = Each(3);
+  EXPECT_EQ("whose element #0 doesn't match", Explain(n, b));
+
+  a.insert(1);
+  a.insert(2);
+  a.insert(3);
+  m = Each(GreaterThan(0));
+  EXPECT_EQ("", Explain(m, a));
+
+  m = Each(GreaterThan(10));
+  EXPECT_EQ("whose element #0 doesn't match, which is 9 less than 10",
+            Explain(m, a));
+}
+
+TEST(EachTest, DescribesItselfCorrectly) {
+  Matcher<vector<int>> m = Each(1);
+  EXPECT_EQ("only contains elements that is equal to 1", Describe(m));
+
+  Matcher<vector<int>> m2 = Not(m);
+  EXPECT_EQ("contains some element that isn't equal to 1", Describe(m2));
+}
+
+TEST(EachTest, MatchesVectorWhenAllElementsMatch) {
+  vector<int> some_vector;
+  EXPECT_THAT(some_vector, Each(1));
+  some_vector.push_back(3);
+  EXPECT_THAT(some_vector, Not(Each(1)));
+  EXPECT_THAT(some_vector, Each(3));
+  some_vector.push_back(1);
+  some_vector.push_back(2);
+  EXPECT_THAT(some_vector, Not(Each(3)));
+  EXPECT_THAT(some_vector, Each(Lt(3.5)));
+
+  vector<std::string> another_vector;
+  another_vector.push_back("fee");
+  EXPECT_THAT(another_vector, Each(std::string("fee")));
+  another_vector.push_back("fie");
+  another_vector.push_back("foe");
+  another_vector.push_back("fum");
+  EXPECT_THAT(another_vector, Not(Each(std::string("fee"))));
+}
+
+TEST(EachTest, MatchesMapWhenAllElementsMatch) {
+  map<const char*, int> my_map;
+  const char* bar = "a string";
+  my_map[bar] = 2;
+  EXPECT_THAT(my_map, Each(make_pair(bar, 2)));
+
+  map<std::string, int> another_map;
+  EXPECT_THAT(another_map, Each(make_pair(std::string("fee"), 1)));
+  another_map["fee"] = 1;
+  EXPECT_THAT(another_map, Each(make_pair(std::string("fee"), 1)));
+  another_map["fie"] = 2;
+  another_map["foe"] = 3;
+  another_map["fum"] = 4;
+  EXPECT_THAT(another_map, Not(Each(make_pair(std::string("fee"), 1))));
+  EXPECT_THAT(another_map, Not(Each(make_pair(std::string("fum"), 1))));
+  EXPECT_THAT(another_map, Each(Pair(_, Gt(0))));
+}
+
+TEST(EachTest, AcceptsMatcher) {
+  const int a[] = {1, 2, 3};
+  EXPECT_THAT(a, Each(Gt(0)));
+  EXPECT_THAT(a, Not(Each(Gt(1))));
+}
+
+TEST(EachTest, WorksForNativeArrayAsTuple) {
+  const int a[] = {1, 2};
+  const int* const pointer = a;
+  EXPECT_THAT(std::make_tuple(pointer, 2), Each(Gt(0)));
+  EXPECT_THAT(std::make_tuple(pointer, 2), Not(Each(Gt(1))));
+}
+
+TEST(EachTest, WorksWithMoveOnly) {
+  ContainerHelper helper;
+  EXPECT_CALL(helper, Call(Each(Pointee(Gt(0)))));
+  helper.Call(MakeUniquePtrs({1, 2}));
+}
+
+// For testing Pointwise().
+class IsHalfOfMatcher {
+ public:
+  template <typename T1, typename T2>
+  bool MatchAndExplain(const std::tuple<T1, T2>& a_pair,
+                       MatchResultListener* listener) const {
+    if (std::get<0>(a_pair) == std::get<1>(a_pair) / 2) {
+      *listener << "where the second is " << std::get<1>(a_pair);
+      return true;
+    } else {
+      *listener << "where the second/2 is " << std::get<1>(a_pair) / 2;
+      return false;
+    }
+  }
+
+  void DescribeTo(ostream* os) const {
+    *os << "are a pair where the first is half of the second";
+  }
+
+  void DescribeNegationTo(ostream* os) const {
+    *os << "are a pair where the first isn't half of the second";
+  }
+};
+
+PolymorphicMatcher<IsHalfOfMatcher> IsHalfOf() {
+  return MakePolymorphicMatcher(IsHalfOfMatcher());
+}
+
+TEST(PointwiseTest, DescribesSelf) {
+  vector<int> rhs;
+  rhs.push_back(1);
+  rhs.push_back(2);
+  rhs.push_back(3);
+  const Matcher<const vector<int>&> m = Pointwise(IsHalfOf(), rhs);
+  EXPECT_EQ(
+      "contains 3 values, where each value and its corresponding value "
+      "in { 1, 2, 3 } are a pair where the first is half of the second",
+      Describe(m));
+  EXPECT_EQ(
+      "doesn't contain exactly 3 values, or contains a value x at some "
+      "index i where x and the i-th value of { 1, 2, 3 } are a pair "
+      "where the first isn't half of the second",
+      DescribeNegation(m));
+}
+
+TEST(PointwiseTest, MakesCopyOfRhs) {
+  list<signed char> rhs;
+  rhs.push_back(2);
+  rhs.push_back(4);
+
+  int lhs[] = {1, 2};
+  const Matcher<const int (&)[2]> m = Pointwise(IsHalfOf(), rhs);
+  EXPECT_THAT(lhs, m);
+
+  // Changing rhs now shouldn't affect m, which made a copy of rhs.
+  rhs.push_back(6);
+  EXPECT_THAT(lhs, m);
+}
+
+TEST(PointwiseTest, WorksForLhsNativeArray) {
+  const int lhs[] = {1, 2, 3};
+  vector<int> rhs;
+  rhs.push_back(2);
+  rhs.push_back(4);
+  rhs.push_back(6);
+  EXPECT_THAT(lhs, Pointwise(Lt(), rhs));
+  EXPECT_THAT(lhs, Not(Pointwise(Gt(), rhs)));
+}
+
+TEST(PointwiseTest, WorksForRhsNativeArray) {
+  const int rhs[] = {1, 2, 3};
+  vector<int> lhs;
+  lhs.push_back(2);
+  lhs.push_back(4);
+  lhs.push_back(6);
+  EXPECT_THAT(lhs, Pointwise(Gt(), rhs));
+  EXPECT_THAT(lhs, Not(Pointwise(Lt(), rhs)));
+}
+
+// Test is effective only with sanitizers.
+TEST(PointwiseTest, WorksForVectorOfBool) {
+  vector<bool> rhs(3, false);
+  rhs[1] = true;
+  vector<bool> lhs = rhs;
+  EXPECT_THAT(lhs, Pointwise(Eq(), rhs));
+  rhs[0] = true;
+  EXPECT_THAT(lhs, Not(Pointwise(Eq(), rhs)));
+}
+
+TEST(PointwiseTest, WorksForRhsInitializerList) {
+  const vector<int> lhs{2, 4, 6};
+  EXPECT_THAT(lhs, Pointwise(Gt(), {1, 2, 3}));
+  EXPECT_THAT(lhs, Not(Pointwise(Lt(), {3, 3, 7})));
+}
+
+TEST(PointwiseTest, RejectsWrongSize) {
+  const double lhs[2] = {1, 2};
+  const int rhs[1] = {0};
+  EXPECT_THAT(lhs, Not(Pointwise(Gt(), rhs)));
+  EXPECT_EQ("which contains 2 values", Explain(Pointwise(Gt(), rhs), lhs));
+
+  const int rhs2[3] = {0, 1, 2};
+  EXPECT_THAT(lhs, Not(Pointwise(Gt(), rhs2)));
+}
+
+TEST(PointwiseTest, RejectsWrongContent) {
+  const double lhs[3] = {1, 2, 3};
+  const int rhs[3] = {2, 6, 4};
+  EXPECT_THAT(lhs, Not(Pointwise(IsHalfOf(), rhs)));
+  EXPECT_EQ(
+      "where the value pair (2, 6) at index #1 don't match, "
+      "where the second/2 is 3",
+      Explain(Pointwise(IsHalfOf(), rhs), lhs));
+}
+
+TEST(PointwiseTest, AcceptsCorrectContent) {
+  const double lhs[3] = {1, 2, 3};
+  const int rhs[3] = {2, 4, 6};
+  EXPECT_THAT(lhs, Pointwise(IsHalfOf(), rhs));
+  EXPECT_EQ("", Explain(Pointwise(IsHalfOf(), rhs), lhs));
+}
+
+TEST(PointwiseTest, AllowsMonomorphicInnerMatcher) {
+  const double lhs[3] = {1, 2, 3};
+  const int rhs[3] = {2, 4, 6};
+  const Matcher<std::tuple<const double&, const int&>> m1 = IsHalfOf();
+  EXPECT_THAT(lhs, Pointwise(m1, rhs));
+  EXPECT_EQ("", Explain(Pointwise(m1, rhs), lhs));
+
+  // This type works as a std::tuple<const double&, const int&> can be
+  // implicitly cast to std::tuple<double, int>.
+  const Matcher<std::tuple<double, int>> m2 = IsHalfOf();
+  EXPECT_THAT(lhs, Pointwise(m2, rhs));
+  EXPECT_EQ("", Explain(Pointwise(m2, rhs), lhs));
+}
+
+MATCHER(PointeeEquals, "Points to an equal value") {
+  return ExplainMatchResult(::testing::Pointee(::testing::get<1>(arg)),
+                            ::testing::get<0>(arg), result_listener);
+}
+
+TEST(PointwiseTest, WorksWithMoveOnly) {
+  ContainerHelper helper;
+  EXPECT_CALL(helper, Call(Pointwise(PointeeEquals(), std::vector<int>{1, 2})));
+  helper.Call(MakeUniquePtrs({1, 2}));
+}
+
+TEST(UnorderedPointwiseTest, DescribesSelf) {
+  vector<int> rhs;
+  rhs.push_back(1);
+  rhs.push_back(2);
+  rhs.push_back(3);
+  const Matcher<const vector<int>&> m = UnorderedPointwise(IsHalfOf(), rhs);
+  EXPECT_EQ(
+      "has 3 elements and there exists some permutation of elements such "
+      "that:\n"
+      " - element #0 and 1 are a pair where the first is half of the second, "
+      "and\n"
+      " - element #1 and 2 are a pair where the first is half of the second, "
+      "and\n"
+      " - element #2 and 3 are a pair where the first is half of the second",
+      Describe(m));
+  EXPECT_EQ(
+      "doesn't have 3 elements, or there exists no permutation of elements "
+      "such that:\n"
+      " - element #0 and 1 are a pair where the first is half of the second, "
+      "and\n"
+      " - element #1 and 2 are a pair where the first is half of the second, "
+      "and\n"
+      " - element #2 and 3 are a pair where the first is half of the second",
+      DescribeNegation(m));
+}
+
+TEST(UnorderedPointwiseTest, MakesCopyOfRhs) {
+  list<signed char> rhs;
+  rhs.push_back(2);
+  rhs.push_back(4);
+
+  int lhs[] = {2, 1};
+  const Matcher<const int (&)[2]> m = UnorderedPointwise(IsHalfOf(), rhs);
+  EXPECT_THAT(lhs, m);
+
+  // Changing rhs now shouldn't affect m, which made a copy of rhs.
+  rhs.push_back(6);
+  EXPECT_THAT(lhs, m);
+}
+
+TEST(UnorderedPointwiseTest, WorksForLhsNativeArray) {
+  const int lhs[] = {1, 2, 3};
+  vector<int> rhs;
+  rhs.push_back(4);
+  rhs.push_back(6);
+  rhs.push_back(2);
+  EXPECT_THAT(lhs, UnorderedPointwise(Lt(), rhs));
+  EXPECT_THAT(lhs, Not(UnorderedPointwise(Gt(), rhs)));
+}
+
+TEST(UnorderedPointwiseTest, WorksForRhsNativeArray) {
+  const int rhs[] = {1, 2, 3};
+  vector<int> lhs;
+  lhs.push_back(4);
+  lhs.push_back(2);
+  lhs.push_back(6);
+  EXPECT_THAT(lhs, UnorderedPointwise(Gt(), rhs));
+  EXPECT_THAT(lhs, Not(UnorderedPointwise(Lt(), rhs)));
+}
+
+TEST(UnorderedPointwiseTest, WorksForRhsInitializerList) {
+  const vector<int> lhs{2, 4, 6};
+  EXPECT_THAT(lhs, UnorderedPointwise(Gt(), {5, 1, 3}));
+  EXPECT_THAT(lhs, Not(UnorderedPointwise(Lt(), {1, 1, 7})));
+}
+
+TEST(UnorderedPointwiseTest, RejectsWrongSize) {
+  const double lhs[2] = {1, 2};
+  const int rhs[1] = {0};
+  EXPECT_THAT(lhs, Not(UnorderedPointwise(Gt(), rhs)));
+  EXPECT_EQ("which has 2 elements\n",
+            Explain(UnorderedPointwise(Gt(), rhs), lhs));
+
+  const int rhs2[3] = {0, 1, 2};
+  EXPECT_THAT(lhs, Not(UnorderedPointwise(Gt(), rhs2)));
+}
+
+TEST(UnorderedPointwiseTest, RejectsWrongContent) {
+  const double lhs[3] = {1, 2, 3};
+  const int rhs[3] = {2, 6, 6};
+  EXPECT_THAT(lhs, Not(UnorderedPointwise(IsHalfOf(), rhs)));
+  EXPECT_EQ(
+      "where the following elements don't match any matchers:\n"
+      "element #1: 2",
+      Explain(UnorderedPointwise(IsHalfOf(), rhs), lhs));
+}
+
+TEST(UnorderedPointwiseTest, AcceptsCorrectContentInSameOrder) {
+  const double lhs[3] = {1, 2, 3};
+  const int rhs[3] = {2, 4, 6};
+  EXPECT_THAT(lhs, UnorderedPointwise(IsHalfOf(), rhs));
+}
+
+TEST(UnorderedPointwiseTest, AcceptsCorrectContentInDifferentOrder) {
+  const double lhs[3] = {1, 2, 3};
+  const int rhs[3] = {6, 4, 2};
+  EXPECT_THAT(lhs, UnorderedPointwise(IsHalfOf(), rhs));
+}
+
+TEST(UnorderedPointwiseTest, AllowsMonomorphicInnerMatcher) {
+  const double lhs[3] = {1, 2, 3};
+  const int rhs[3] = {4, 6, 2};
+  const Matcher<std::tuple<const double&, const int&>> m1 = IsHalfOf();
+  EXPECT_THAT(lhs, UnorderedPointwise(m1, rhs));
+
+  // This type works as a std::tuple<const double&, const int&> can be
+  // implicitly cast to std::tuple<double, int>.
+  const Matcher<std::tuple<double, int>> m2 = IsHalfOf();
+  EXPECT_THAT(lhs, UnorderedPointwise(m2, rhs));
+}
+
+TEST(UnorderedPointwiseTest, WorksWithMoveOnly) {
+  ContainerHelper helper;
+  EXPECT_CALL(helper, Call(UnorderedPointwise(PointeeEquals(),
+                                              std::vector<int>{1, 2})));
+  helper.Call(MakeUniquePtrs({2, 1}));
+}
+
+TEST(PointeeTest, WorksOnMoveOnlyType) {
+  std::unique_ptr<int> p(new int(3));
+  EXPECT_THAT(p, Pointee(Eq(3)));
+  EXPECT_THAT(p, Not(Pointee(Eq(2))));
+}
+
+class PredicateFormatterFromMatcherTest : public ::testing::Test {
+ protected:
+  enum Behavior { kInitialSuccess, kAlwaysFail, kFlaky };
+
+  // A matcher that can return different results when used multiple times on the
+  // same input. No real matcher should do this; but this lets us test that we
+  // detect such behavior and fail appropriately.
+  class MockMatcher : public MatcherInterface<Behavior> {
+   public:
+    bool MatchAndExplain(Behavior behavior,
+                         MatchResultListener* listener) const override {
+      *listener << "[MatchAndExplain]";
+      switch (behavior) {
+        case kInitialSuccess:
+          // The first call to MatchAndExplain should use a "not interested"
+          // listener; so this is expected to return |true|. There should be no
+          // subsequent calls.
+          return !listener->IsInterested();
+
+        case kAlwaysFail:
+          return false;
+
+        case kFlaky:
+          // The first call to MatchAndExplain should use a "not interested"
+          // listener; so this will return |false|. Subsequent calls should have
+          // an "interested" listener; so this will return |true|, thus
+          // simulating a flaky matcher.
+          return listener->IsInterested();
+      }
+
+      GTEST_LOG_(FATAL) << "This should never be reached";
+      return false;
+    }
+
+    void DescribeTo(ostream* os) const override { *os << "[DescribeTo]"; }
+
+    void DescribeNegationTo(ostream* os) const override {
+      *os << "[DescribeNegationTo]";
+    }
+  };
+
+  AssertionResult RunPredicateFormatter(Behavior behavior) {
+    auto matcher = MakeMatcher(new MockMatcher);
+    PredicateFormatterFromMatcher<Matcher<Behavior>> predicate_formatter(
+        matcher);
+    return predicate_formatter("dummy-name", behavior);
+  }
+};
+
+TEST_F(PredicateFormatterFromMatcherTest, ShortCircuitOnSuccess) {
+  AssertionResult result = RunPredicateFormatter(kInitialSuccess);
+  EXPECT_TRUE(result);  // Implicit cast to bool.
+  std::string expect;
+  EXPECT_EQ(expect, result.message());
+}
+
+TEST_F(PredicateFormatterFromMatcherTest, NoShortCircuitOnFailure) {
+  AssertionResult result = RunPredicateFormatter(kAlwaysFail);
+  EXPECT_FALSE(result);  // Implicit cast to bool.
+  std::string expect =
+      "Value of: dummy-name\nExpected: [DescribeTo]\n"
+      "  Actual: 1" +
+      OfType(internal::GetTypeName<Behavior>()) + ", [MatchAndExplain]";
+  EXPECT_EQ(expect, result.message());
+}
+
+TEST_F(PredicateFormatterFromMatcherTest, DetectsFlakyShortCircuit) {
+  AssertionResult result = RunPredicateFormatter(kFlaky);
+  EXPECT_FALSE(result);  // Implicit cast to bool.
+  std::string expect =
+      "Value of: dummy-name\nExpected: [DescribeTo]\n"
+      "  The matcher failed on the initial attempt; but passed when rerun to "
+      "generate the explanation.\n"
+      "  Actual: 2" +
+      OfType(internal::GetTypeName<Behavior>()) + ", [MatchAndExplain]";
+  EXPECT_EQ(expect, result.message());
+}
+
+// Tests for ElementsAre().
+
+TEST(ElementsAreTest, CanDescribeExpectingNoElement) {
+  Matcher<const vector<int>&> m = ElementsAre();
+  EXPECT_EQ("is empty", Describe(m));
+}
+
+TEST(ElementsAreTest, CanDescribeExpectingOneElement) {
+  Matcher<vector<int>> m = ElementsAre(Gt(5));
+  EXPECT_EQ("has 1 element that is > 5", Describe(m));
+}
+
+TEST(ElementsAreTest, CanDescribeExpectingManyElements) {
+  Matcher<list<std::string>> m = ElementsAre(StrEq("one"), "two");
+  EXPECT_EQ(
+      "has 2 elements where\n"
+      "element #0 is equal to \"one\",\n"
+      "element #1 is equal to \"two\"",
+      Describe(m));
+}
+
+TEST(ElementsAreTest, CanDescribeNegationOfExpectingNoElement) {
+  Matcher<vector<int>> m = ElementsAre();
+  EXPECT_EQ("isn't empty", DescribeNegation(m));
+}
+
+TEST(ElementsAreTest, CanDescribeNegationOfExpectingOneElement) {
+  Matcher<const list<int>&> m = ElementsAre(Gt(5));
+  EXPECT_EQ(
+      "doesn't have 1 element, or\n"
+      "element #0 isn't > 5",
+      DescribeNegation(m));
+}
+
+TEST(ElementsAreTest, CanDescribeNegationOfExpectingManyElements) {
+  Matcher<const list<std::string>&> m = ElementsAre("one", "two");
+  EXPECT_EQ(
+      "doesn't have 2 elements, or\n"
+      "element #0 isn't equal to \"one\", or\n"
+      "element #1 isn't equal to \"two\"",
+      DescribeNegation(m));
+}
+
+TEST(ElementsAreTest, DoesNotExplainTrivialMatch) {
+  Matcher<const list<int>&> m = ElementsAre(1, Ne(2));
+
+  list<int> test_list;
+  test_list.push_back(1);
+  test_list.push_back(3);
+  EXPECT_EQ("", Explain(m, test_list));  // No need to explain anything.
+}
+
+TEST_P(ElementsAreTestP, ExplainsNonTrivialMatch) {
+  Matcher<const vector<int>&> m =
+      ElementsAre(GreaterThan(1), 0, GreaterThan(2));
+
+  const int a[] = {10, 0, 100};
+  vector<int> test_vector(std::begin(a), std::end(a));
+  EXPECT_EQ(
+      "whose element #0 matches, which is 9 more than 1,\n"
+      "and whose element #2 matches, which is 98 more than 2",
+      Explain(m, test_vector));
+}
+
+TEST(ElementsAreTest, CanExplainMismatchWrongSize) {
+  Matcher<const list<int>&> m = ElementsAre(1, 3);
+
+  list<int> test_list;
+  // No need to explain when the container is empty.
+  EXPECT_EQ("", Explain(m, test_list));
+
+  test_list.push_back(1);
+  EXPECT_EQ("which has 1 element", Explain(m, test_list));
+}
+
+TEST_P(ElementsAreTestP, CanExplainMismatchRightSize) {
+  Matcher<const vector<int>&> m = ElementsAre(1, GreaterThan(5));
+
+  vector<int> v;
+  v.push_back(2);
+  v.push_back(1);
+  EXPECT_EQ(Explain(m, v), "whose element #0 (2) isn't equal to 1");
+
+  v[0] = 1;
+  EXPECT_EQ(Explain(m, v),
+            "whose element #1 (1) is <= 5, which is 4 less than 5");
+}
+
+TEST(ElementsAreTest, MatchesOneElementVector) {
+  vector<std::string> test_vector;
+  test_vector.push_back("test string");
+
+  EXPECT_THAT(test_vector, ElementsAre(StrEq("test string")));
+}
+
+TEST(ElementsAreTest, MatchesOneElementList) {
+  list<std::string> test_list;
+  test_list.push_back("test string");
+
+  EXPECT_THAT(test_list, ElementsAre("test string"));
+}
+
+TEST(ElementsAreTest, MatchesThreeElementVector) {
+  vector<std::string> test_vector;
+  test_vector.push_back("one");
+  test_vector.push_back("two");
+  test_vector.push_back("three");
+
+  EXPECT_THAT(test_vector, ElementsAre("one", StrEq("two"), _));
+}
+
+TEST(ElementsAreTest, MatchesOneElementEqMatcher) {
+  vector<int> test_vector;
+  test_vector.push_back(4);
+
+  EXPECT_THAT(test_vector, ElementsAre(Eq(4)));
+}
+
+TEST(ElementsAreTest, MatchesOneElementAnyMatcher) {
+  vector<int> test_vector;
+  test_vector.push_back(4);
+
+  EXPECT_THAT(test_vector, ElementsAre(_));
+}
+
+TEST(ElementsAreTest, MatchesOneElementValue) {
+  vector<int> test_vector;
+  test_vector.push_back(4);
+
+  EXPECT_THAT(test_vector, ElementsAre(4));
+}
+
+TEST(ElementsAreTest, MatchesThreeElementsMixedMatchers) {
+  vector<int> test_vector;
+  test_vector.push_back(1);
+  test_vector.push_back(2);
+  test_vector.push_back(3);
+
+  EXPECT_THAT(test_vector, ElementsAre(1, Eq(2), _));
+}
+
+TEST(ElementsAreTest, MatchesTenElementVector) {
+  const int a[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+  vector<int> test_vector(std::begin(a), std::end(a));
+
+  EXPECT_THAT(test_vector,
+              // The element list can contain values and/or matchers
+              // of different types.
+              ElementsAre(0, Ge(0), _, 3, 4, Ne(2), Eq(6), 7, 8, _));
+}
+
+TEST(ElementsAreTest, DoesNotMatchWrongSize) {
+  vector<std::string> test_vector;
+  test_vector.push_back("test string");
+  test_vector.push_back("test string");
+
+  Matcher<vector<std::string>> m = ElementsAre(StrEq("test string"));
+  EXPECT_FALSE(m.Matches(test_vector));
+}
+
+TEST(ElementsAreTest, DoesNotMatchWrongValue) {
+  vector<std::string> test_vector;
+  test_vector.push_back("other string");
+
+  Matcher<vector<std::string>> m = ElementsAre(StrEq("test string"));
+  EXPECT_FALSE(m.Matches(test_vector));
+}
+
+TEST(ElementsAreTest, DoesNotMatchWrongOrder) {
+  vector<std::string> test_vector;
+  test_vector.push_back("one");
+  test_vector.push_back("three");
+  test_vector.push_back("two");
+
+  Matcher<vector<std::string>> m =
+      ElementsAre(StrEq("one"), StrEq("two"), StrEq("three"));
+  EXPECT_FALSE(m.Matches(test_vector));
+}
+
+TEST(ElementsAreTest, WorksForNestedContainer) {
+  constexpr std::array<const char*, 2> strings = {{"Hi", "world"}};
+
+  vector<list<char>> nested;
+  for (const auto& s : strings) {
+    nested.emplace_back(s, s + strlen(s));
+  }
+
+  EXPECT_THAT(nested, ElementsAre(ElementsAre('H', Ne('e')),
+                                  ElementsAre('w', 'o', _, _, 'd')));
+  EXPECT_THAT(nested, Not(ElementsAre(ElementsAre('H', 'e'),
+                                      ElementsAre('w', 'o', _, _, 'd'))));
+}
+
+TEST(ElementsAreTest, WorksWithByRefElementMatchers) {
+  int a[] = {0, 1, 2};
+  vector<int> v(std::begin(a), std::end(a));
+
+  EXPECT_THAT(v, ElementsAre(Ref(v[0]), Ref(v[1]), Ref(v[2])));
+  EXPECT_THAT(v, Not(ElementsAre(Ref(v[0]), Ref(v[1]), Ref(a[2]))));
+}
+
+TEST(ElementsAreTest, WorksWithContainerPointerUsingPointee) {
+  int a[] = {0, 1, 2};
+  vector<int> v(std::begin(a), std::end(a));
+
+  EXPECT_THAT(&v, Pointee(ElementsAre(0, 1, _)));
+  EXPECT_THAT(&v, Not(Pointee(ElementsAre(0, _, 3))));
+}
+
+TEST(ElementsAreTest, WorksWithNativeArrayPassedByReference) {
+  int array[] = {0, 1, 2};
+  EXPECT_THAT(array, ElementsAre(0, 1, _));
+  EXPECT_THAT(array, Not(ElementsAre(1, _, _)));
+  EXPECT_THAT(array, Not(ElementsAre(0, _)));
+}
+
+class NativeArrayPassedAsPointerAndSize {
+ public:
+  NativeArrayPassedAsPointerAndSize() = default;
+
+  MOCK_METHOD(void, Helper, (int* array, int size));
+
+ private:
+  NativeArrayPassedAsPointerAndSize(const NativeArrayPassedAsPointerAndSize&) =
+      delete;
+  NativeArrayPassedAsPointerAndSize& operator=(
+      const NativeArrayPassedAsPointerAndSize&) = delete;
+};
+
+TEST(ElementsAreTest, WorksWithNativeArrayPassedAsPointerAndSize) {
+  int array[] = {0, 1};
+  ::std::tuple<int*, size_t> array_as_tuple(array, 2);
+  EXPECT_THAT(array_as_tuple, ElementsAre(0, 1));
+  EXPECT_THAT(array_as_tuple, Not(ElementsAre(0)));
+
+  NativeArrayPassedAsPointerAndSize helper;
+  EXPECT_CALL(helper, Helper(_, _)).With(ElementsAre(0, 1));
+  helper.Helper(array, 2);
+}
+
+TEST(ElementsAreTest, WorksWithTwoDimensionalNativeArray) {
+  const char a2[][3] = {"hi", "lo"};
+  EXPECT_THAT(a2, ElementsAre(ElementsAre('h', 'i', '\0'),
+                              ElementsAre('l', 'o', '\0')));
+  EXPECT_THAT(a2, ElementsAre(StrEq("hi"), StrEq("lo")));
+  EXPECT_THAT(a2, ElementsAre(Not(ElementsAre('h', 'o', '\0')),
+                              ElementsAre('l', 'o', '\0')));
+}
+
+TEST(ElementsAreTest, AcceptsStringLiteral) {
+  std::string array[] = {"hi", "one", "two"};
+  EXPECT_THAT(array, ElementsAre("hi", "one", "two"));
+  EXPECT_THAT(array, Not(ElementsAre("hi", "one", "too")));
+}
+
+// Declared here with the size unknown.  Defined AFTER the following test.
+extern const char kHi[];
+
+TEST(ElementsAreTest, AcceptsArrayWithUnknownSize) {
+  // The size of kHi is not known in this test, but ElementsAre() should
+  // still accept it.
+
+  std::string array1[] = {"hi"};
+  EXPECT_THAT(array1, ElementsAre(kHi));
+
+  std::string array2[] = {"ho"};
+  EXPECT_THAT(array2, Not(ElementsAre(kHi)));
+}
+
+const char kHi[] = "hi";
+
+TEST(ElementsAreTest, MakesCopyOfArguments) {
+  int x = 1;
+  int y = 2;
+  // This should make a copy of x and y.
+  ::testing::internal::ElementsAreMatcher<std::tuple<int, int>>
+      polymorphic_matcher = ElementsAre(x, y);
+  // Changing x and y now shouldn't affect the meaning of the above matcher.
+  x = y = 0;
+  const int array1[] = {1, 2};
+  EXPECT_THAT(array1, polymorphic_matcher);
+  const int array2[] = {0, 0};
+  EXPECT_THAT(array2, Not(polymorphic_matcher));
+}
+
+// Tests for ElementsAreArray().  Since ElementsAreArray() shares most
+// of the implementation with ElementsAre(), we don't test it as
+// thoroughly here.
+
+TEST(ElementsAreArrayTest, CanBeCreatedWithValueArray) {
+  const int a[] = {1, 2, 3};
+
+  vector<int> test_vector(std::begin(a), std::end(a));
+  EXPECT_THAT(test_vector, ElementsAreArray(a));
+
+  test_vector[2] = 0;
+  EXPECT_THAT(test_vector, Not(ElementsAreArray(a)));
+}
+
+TEST(ElementsAreArrayTest, CanBeCreatedWithArraySize) {
+  std::array<const char*, 3> a = {{"one", "two", "three"}};
+
+  vector<std::string> test_vector(std::begin(a), std::end(a));
+  EXPECT_THAT(test_vector, ElementsAreArray(a.data(), a.size()));
+
+  const char** p = a.data();
+  test_vector[0] = "1";
+  EXPECT_THAT(test_vector, Not(ElementsAreArray(p, a.size())));
+}
+
+TEST(ElementsAreArrayTest, CanBeCreatedWithoutArraySize) {
+  const char* a[] = {"one", "two", "three"};
+
+  vector<std::string> test_vector(std::begin(a), std::end(a));
+  EXPECT_THAT(test_vector, ElementsAreArray(a));
+
+  test_vector[0] = "1";
+  EXPECT_THAT(test_vector, Not(ElementsAreArray(a)));
+}
+
+TEST(ElementsAreArrayTest, CanBeCreatedWithMatcherArray) {
+  const Matcher<std::string> kMatcherArray[] = {StrEq("one"), StrEq("two"),
+                                                StrEq("three")};
+
+  vector<std::string> test_vector;
+  test_vector.push_back("one");
+  test_vector.push_back("two");
+  test_vector.push_back("three");
+  EXPECT_THAT(test_vector, ElementsAreArray(kMatcherArray));
+
+  test_vector.push_back("three");
+  EXPECT_THAT(test_vector, Not(ElementsAreArray(kMatcherArray)));
+}
+
+TEST(ElementsAreArrayTest, CanBeCreatedWithVector) {
+  const int a[] = {1, 2, 3};
+  vector<int> test_vector(std::begin(a), std::end(a));
+  const vector<int> expected(std::begin(a), std::end(a));
+  EXPECT_THAT(test_vector, ElementsAreArray(expected));
+  test_vector.push_back(4);
+  EXPECT_THAT(test_vector, Not(ElementsAreArray(expected)));
+}
+
+TEST(ElementsAreArrayTest, TakesInitializerList) {
+  const int a[5] = {1, 2, 3, 4, 5};
+  EXPECT_THAT(a, ElementsAreArray({1, 2, 3, 4, 5}));
+  EXPECT_THAT(a, Not(ElementsAreArray({1, 2, 3, 5, 4})));
+  EXPECT_THAT(a, Not(ElementsAreArray({1, 2, 3, 4, 6})));
+}
+
+TEST(ElementsAreArrayTest, TakesInitializerListOfCStrings) {
+  const std::string a[5] = {"a", "b", "c", "d", "e"};
+  EXPECT_THAT(a, ElementsAreArray({"a", "b", "c", "d", "e"}));
+  EXPECT_THAT(a, Not(ElementsAreArray({"a", "b", "c", "e", "d"})));
+  EXPECT_THAT(a, Not(ElementsAreArray({"a", "b", "c", "d", "ef"})));
+}
+
+TEST(ElementsAreArrayTest, TakesInitializerListOfSameTypedMatchers) {
+  const int a[5] = {1, 2, 3, 4, 5};
+  EXPECT_THAT(a, ElementsAreArray({Eq(1), Eq(2), Eq(3), Eq(4), Eq(5)}));
+  EXPECT_THAT(a, Not(ElementsAreArray({Eq(1), Eq(2), Eq(3), Eq(4), Eq(6)})));
+}
+
+TEST(ElementsAreArrayTest, TakesInitializerListOfDifferentTypedMatchers) {
+  const int a[5] = {1, 2, 3, 4, 5};
+  // The compiler cannot infer the type of the initializer list if its
+  // elements have different types.  We must explicitly specify the
+  // unified element type in this case.
+  EXPECT_THAT(
+      a, ElementsAreArray<Matcher<int>>({Eq(1), Ne(-2), Ge(3), Le(4), Eq(5)}));
+  EXPECT_THAT(a, Not(ElementsAreArray<Matcher<int>>(
+                     {Eq(1), Ne(-2), Ge(3), Le(4), Eq(6)})));
+}
+
+TEST(ElementsAreArrayTest, CanBeCreatedWithMatcherVector) {
+  const int a[] = {1, 2, 3};
+  const Matcher<int> kMatchers[] = {Eq(1), Eq(2), Eq(3)};
+  vector<int> test_vector(std::begin(a), std::end(a));
+  const vector<Matcher<int>> expected(std::begin(kMatchers),
+                                      std::end(kMatchers));
+  EXPECT_THAT(test_vector, ElementsAreArray(expected));
+  test_vector.push_back(4);
+  EXPECT_THAT(test_vector, Not(ElementsAreArray(expected)));
+}
+
+TEST(ElementsAreArrayTest, CanBeCreatedWithIteratorRange) {
+  const int a[] = {1, 2, 3};
+  const vector<int> test_vector(std::begin(a), std::end(a));
+  const vector<int> expected(std::begin(a), std::end(a));
+  EXPECT_THAT(test_vector, ElementsAreArray(expected.begin(), expected.end()));
+  // Pointers are iterators, too.
+  EXPECT_THAT(test_vector, ElementsAreArray(std::begin(a), std::end(a)));
+  // The empty range of NULL pointers should also be okay.
+  int* const null_int = nullptr;
+  EXPECT_THAT(test_vector, Not(ElementsAreArray(null_int, null_int)));
+  EXPECT_THAT((vector<int>()), ElementsAreArray(null_int, null_int));
+}
+
+// Since ElementsAre() and ElementsAreArray() share much of the
+// implementation, we only do a test for native arrays here.
+TEST(ElementsAreArrayTest, WorksWithNativeArray) {
+  ::std::string a[] = {"hi", "ho"};
+  ::std::string b[] = {"hi", "ho"};
+
+  EXPECT_THAT(a, ElementsAreArray(b));
+  EXPECT_THAT(a, ElementsAreArray(b, 2));
+  EXPECT_THAT(a, Not(ElementsAreArray(b, 1)));
+}
+
+TEST(ElementsAreArrayTest, SourceLifeSpan) {
+  const int a[] = {1, 2, 3};
+  vector<int> test_vector(std::begin(a), std::end(a));
+  vector<int> expect(std::begin(a), std::end(a));
+  ElementsAreArrayMatcher<int> matcher_maker =
+      ElementsAreArray(expect.begin(), expect.end());
+  EXPECT_THAT(test_vector, matcher_maker);
+  // Changing in place the values that initialized matcher_maker should not
+  // affect matcher_maker anymore. It should have made its own copy of them.
+  for (int& i : expect) {
+    i += 10;
+  }
+  EXPECT_THAT(test_vector, matcher_maker);
+  test_vector.push_back(3);
+  EXPECT_THAT(test_vector, Not(matcher_maker));
+}
+
+// Tests Contains().
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(ContainsTest);
+
+TEST(ContainsTest, ListMatchesWhenElementIsInContainer) {
+  list<int> some_list;
+  some_list.push_back(3);
+  some_list.push_back(1);
+  some_list.push_back(2);
+  some_list.push_back(3);
+  EXPECT_THAT(some_list, Contains(1));
+  EXPECT_THAT(some_list, Contains(Gt(2.5)));
+  EXPECT_THAT(some_list, Contains(Eq(2.0f)));
+
+  list<std::string> another_list;
+  another_list.push_back("fee");
+  another_list.push_back("fie");
+  another_list.push_back("foe");
+  another_list.push_back("fum");
+  EXPECT_THAT(another_list, Contains(std::string("fee")));
+}
+
+TEST(ContainsTest, ListDoesNotMatchWhenElementIsNotInContainer) {
+  list<int> some_list;
+  some_list.push_back(3);
+  some_list.push_back(1);
+  EXPECT_THAT(some_list, Not(Contains(4)));
+}
+
+TEST(ContainsTest, SetMatchesWhenElementIsInContainer) {
+  set<int> some_set;
+  some_set.insert(3);
+  some_set.insert(1);
+  some_set.insert(2);
+  EXPECT_THAT(some_set, Contains(Eq(1.0)));
+  EXPECT_THAT(some_set, Contains(Eq(3.0f)));
+  EXPECT_THAT(some_set, Contains(2));
+
+  set<std::string> another_set;
+  another_set.insert("fee");
+  another_set.insert("fie");
+  another_set.insert("foe");
+  another_set.insert("fum");
+  EXPECT_THAT(another_set, Contains(Eq(std::string("fum"))));
+}
+
+TEST(ContainsTest, SetDoesNotMatchWhenElementIsNotInContainer) {
+  set<int> some_set;
+  some_set.insert(3);
+  some_set.insert(1);
+  EXPECT_THAT(some_set, Not(Contains(4)));
+
+  set<std::string> c_string_set;
+  c_string_set.insert("hello");
+  EXPECT_THAT(c_string_set, Not(Contains(std::string("goodbye"))));
+}
+
+TEST_P(ContainsTestP, ExplainsMatchResultCorrectly) {
+  const int a[2] = {1, 2};
+  Matcher<const int (&)[2]> m = Contains(2);
+  EXPECT_EQ("whose element #1 matches", Explain(m, a));
+
+  m = Contains(3);
+  EXPECT_EQ("", Explain(m, a));
+
+  m = Contains(GreaterThan(0));
+  EXPECT_EQ("whose element #0 matches, which is 1 more than 0", Explain(m, a));
+
+  m = Contains(GreaterThan(10));
+  EXPECT_EQ("", Explain(m, a));
+}
+
+TEST(ContainsTest, DescribesItselfCorrectly) {
+  Matcher<vector<int>> m = Contains(1);
+  EXPECT_EQ("contains at least one element that is equal to 1", Describe(m));
+
+  Matcher<vector<int>> m2 = Not(m);
+  EXPECT_EQ("doesn't contain any element that is equal to 1", Describe(m2));
+}
+
+TEST(ContainsTest, MapMatchesWhenElementIsInContainer) {
+  map<std::string, int> my_map;
+  const char* bar = "a string";
+  my_map[bar] = 2;
+  EXPECT_THAT(my_map, Contains(pair<const char* const, int>(bar, 2)));
+
+  map<std::string, int> another_map;
+  another_map["fee"] = 1;
+  another_map["fie"] = 2;
+  another_map["foe"] = 3;
+  another_map["fum"] = 4;
+  EXPECT_THAT(another_map,
+              Contains(pair<const std::string, int>(std::string("fee"), 1)));
+  EXPECT_THAT(another_map, Contains(pair<const std::string, int>("fie", 2)));
+}
+
+TEST(ContainsTest, MapDoesNotMatchWhenElementIsNotInContainer) {
+  map<int, int> some_map;
+  some_map[1] = 11;
+  some_map[2] = 22;
+  EXPECT_THAT(some_map, Not(Contains(pair<const int, int>(2, 23))));
+}
+
+TEST(ContainsTest, ArrayMatchesWhenElementIsInContainer) {
+  const char* string_array[] = {"fee", "fie", "foe", "fum"};
+  EXPECT_THAT(string_array, Contains(Eq(std::string("fum"))));
+}
+
+TEST(ContainsTest, ArrayDoesNotMatchWhenElementIsNotInContainer) {
+  int int_array[] = {1, 2, 3, 4};
+  EXPECT_THAT(int_array, Not(Contains(5)));
+}
+
+TEST(ContainsTest, AcceptsMatcher) {
+  const int a[] = {1, 2, 3};
+  EXPECT_THAT(a, Contains(Gt(2)));
+  EXPECT_THAT(a, Not(Contains(Gt(4))));
+}
+
+TEST(ContainsTest, WorksForNativeArrayAsTuple) {
+  const int a[] = {1, 2};
+  const int* const pointer = a;
+  EXPECT_THAT(std::make_tuple(pointer, 2), Contains(1));
+  EXPECT_THAT(std::make_tuple(pointer, 2), Not(Contains(Gt(3))));
+}
+
+TEST(ContainsTest, WorksForTwoDimensionalNativeArray) {
+  int a[][3] = {{1, 2, 3}, {4, 5, 6}};
+  EXPECT_THAT(a, Contains(ElementsAre(4, 5, 6)));
+  EXPECT_THAT(a, Contains(Contains(5)));
+  EXPECT_THAT(a, Not(Contains(ElementsAre(3, 4, 5))));
+  EXPECT_THAT(a, Contains(Not(Contains(5))));
+}
+
+}  // namespace
+}  // namespace gmock_matchers_test
+}  // namespace testing
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  // 4244 4100

googletest/googlemock/test/gmock-matchers-misc_test.cc

+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file tests some commonly used argument matchers.
+
+#include <array>
+#include <cstdint>
+#include <memory>
+#include <ostream>
+#include <string>
+#include <tuple>
+#include <utility>
+#include <vector>
+
+#include "gmock/gmock.h"
+#include "test/gmock-matchers_test.h"
+#include "gtest/gtest.h"
+
+// Silence warning C4244: 'initializing': conversion from 'int' to 'short',
+// possible loss of data and C4100, unreferenced local parameter
+GTEST_DISABLE_MSC_WARNINGS_PUSH_(4244 4100)
+
+namespace testing {
+namespace gmock_matchers_test {
+namespace {
+
+TEST(AddressTest, NonConst) {
+  int n = 1;
+  const Matcher<int> m = Address(Eq(&n));
+
+  EXPECT_TRUE(m.Matches(n));
+
+  int other = 5;
+
+  EXPECT_FALSE(m.Matches(other));
+
+  int& n_ref = n;
+
+  EXPECT_TRUE(m.Matches(n_ref));
+}
+
+TEST(AddressTest, Const) {
+  const int n = 1;
+  const Matcher<int> m = Address(Eq(&n));
+
+  EXPECT_TRUE(m.Matches(n));
+
+  int other = 5;
+
+  EXPECT_FALSE(m.Matches(other));
+}
+
+TEST(AddressTest, MatcherDoesntCopy) {
+  std::unique_ptr<int> n(new int(1));
+  const Matcher<std::unique_ptr<int>> m = Address(Eq(&n));
+
+  EXPECT_TRUE(m.Matches(n));
+}
+
+TEST(AddressTest, Describe) {
+  Matcher<int> matcher = Address(_);
+  EXPECT_EQ("has address that is anything", Describe(matcher));
+  EXPECT_EQ("does not have address that is anything",
+            DescribeNegation(matcher));
+}
+
+// The following two tests verify that values without a public copy
+// ctor can be used as arguments to matchers like Eq(), Ge(), and etc
+// with the help of ByRef().
+
+class NotCopyable {
+ public:
+  explicit NotCopyable(int a_value) : value_(a_value) {}
+
+  int value() const { return value_; }
+
+  bool operator==(const NotCopyable& rhs) const {
+    return value() == rhs.value();
+  }
+
+  bool operator>=(const NotCopyable& rhs) const {
+    return value() >= rhs.value();
+  }
+
+ private:
+  int value_;
+
+  NotCopyable(const NotCopyable&) = delete;
+  NotCopyable& operator=(const NotCopyable&) = delete;
+};
+
+TEST(ByRefTest, AllowsNotCopyableConstValueInMatchers) {
+  const NotCopyable const_value1(1);
+  const Matcher<const NotCopyable&> m = Eq(ByRef(const_value1));
+
+  const NotCopyable n1(1), n2(2);
+  EXPECT_TRUE(m.Matches(n1));
+  EXPECT_FALSE(m.Matches(n2));
+}
+
+TEST(ByRefTest, AllowsNotCopyableValueInMatchers) {
+  NotCopyable value2(2);
+  const Matcher<NotCopyable&> m = Ge(ByRef(value2));
+
+  NotCopyable n1(1), n2(2);
+  EXPECT_FALSE(m.Matches(n1));
+  EXPECT_TRUE(m.Matches(n2));
+}
+
+TEST(IsEmptyTest, ImplementsIsEmpty) {
+  vector<int> container;
+  EXPECT_THAT(container, IsEmpty());
+  container.push_back(0);
+  EXPECT_THAT(container, Not(IsEmpty()));
+  container.push_back(1);
+  EXPECT_THAT(container, Not(IsEmpty()));
+}
+
+TEST(IsEmptyTest, WorksWithString) {
+  std::string text;
+  EXPECT_THAT(text, IsEmpty());
+  text = "foo";
+  EXPECT_THAT(text, Not(IsEmpty()));
+  text = std::string("\0", 1);
+  EXPECT_THAT(text, Not(IsEmpty()));
+}
+
+TEST(IsEmptyTest, CanDescribeSelf) {
+  Matcher<vector<int>> m = IsEmpty();
+  EXPECT_EQ("is empty", Describe(m));
+  EXPECT_EQ("isn't empty", DescribeNegation(m));
+}
+
+TEST(IsEmptyTest, ExplainsResult) {
+  Matcher<vector<int>> m = IsEmpty();
+  vector<int> container;
+  EXPECT_EQ("", Explain(m, container));
+  container.push_back(0);
+  EXPECT_EQ("whose size is 1", Explain(m, container));
+}
+
+TEST(IsEmptyTest, WorksWithMoveOnly) {
+  ContainerHelper helper;
+  EXPECT_CALL(helper, Call(IsEmpty()));
+  helper.Call({});
+}
+
+TEST(IsTrueTest, IsTrueIsFalse) {
+  EXPECT_THAT(true, IsTrue());
+  EXPECT_THAT(false, IsFalse());
+  EXPECT_THAT(true, Not(IsFalse()));
+  EXPECT_THAT(false, Not(IsTrue()));
+  EXPECT_THAT(0, Not(IsTrue()));
+  EXPECT_THAT(0, IsFalse());
+  EXPECT_THAT(nullptr, Not(IsTrue()));
+  EXPECT_THAT(nullptr, IsFalse());
+  EXPECT_THAT(-1, IsTrue());
+  EXPECT_THAT(-1, Not(IsFalse()));
+  EXPECT_THAT(1, IsTrue());
+  EXPECT_THAT(1, Not(IsFalse()));
+  EXPECT_THAT(2, IsTrue());
+  EXPECT_THAT(2, Not(IsFalse()));
+  int a = 42;
+  EXPECT_THAT(a, IsTrue());
+  EXPECT_THAT(a, Not(IsFalse()));
+  EXPECT_THAT(&a, IsTrue());
+  EXPECT_THAT(&a, Not(IsFalse()));
+  EXPECT_THAT(false, Not(IsTrue()));
+  EXPECT_THAT(true, Not(IsFalse()));
+  EXPECT_THAT(std::true_type(), IsTrue());
+  EXPECT_THAT(std::true_type(), Not(IsFalse()));
+  EXPECT_THAT(std::false_type(), IsFalse());
+  EXPECT_THAT(std::false_type(), Not(IsTrue()));
+  EXPECT_THAT(nullptr, Not(IsTrue()));
+  EXPECT_THAT(nullptr, IsFalse());
+  std::unique_ptr<int> null_unique;
+  std::unique_ptr<int> nonnull_unique(new int(0));
+  EXPECT_THAT(null_unique, Not(IsTrue()));
+  EXPECT_THAT(null_unique, IsFalse());
+  EXPECT_THAT(nonnull_unique, IsTrue());
+  EXPECT_THAT(nonnull_unique, Not(IsFalse()));
+}
+
+#ifdef GTEST_HAS_TYPED_TEST
+// Tests ContainerEq with different container types, and
+// different element types.
+
+template <typename T>
+class ContainerEqTest : public testing::Test {};
+
+typedef testing::Types<set<int>, vector<size_t>, multiset<size_t>, list<int>>
+    ContainerEqTestTypes;
+
+TYPED_TEST_SUITE(ContainerEqTest, ContainerEqTestTypes);
+
+// Tests that the filled container is equal to itself.
+TYPED_TEST(ContainerEqTest, EqualsSelf) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  TypeParam my_set(vals, vals + 6);
+  const Matcher<TypeParam> m = ContainerEq(my_set);
+  EXPECT_TRUE(m.Matches(my_set));
+  EXPECT_EQ("", Explain(m, my_set));
+}
+
+// Tests that missing values are reported.
+TYPED_TEST(ContainerEqTest, ValueMissing) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {2, 1, 8, 5};
+  TypeParam my_set(vals, vals + 6);
+  TypeParam test_set(test_vals, test_vals + 4);
+  const Matcher<TypeParam> m = ContainerEq(my_set);
+  EXPECT_FALSE(m.Matches(test_set));
+  EXPECT_EQ("which doesn't have these expected elements: 3",
+            Explain(m, test_set));
+}
+
+// Tests that added values are reported.
+TYPED_TEST(ContainerEqTest, ValueAdded) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {1, 2, 3, 5, 8, 46};
+  TypeParam my_set(vals, vals + 6);
+  TypeParam test_set(test_vals, test_vals + 6);
+  const Matcher<const TypeParam&> m = ContainerEq(my_set);
+  EXPECT_FALSE(m.Matches(test_set));
+  EXPECT_EQ("which has these unexpected elements: 46", Explain(m, test_set));
+}
+
+// Tests that added and missing values are reported together.
+TYPED_TEST(ContainerEqTest, ValueAddedAndRemoved) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {1, 2, 3, 8, 46};
+  TypeParam my_set(vals, vals + 6);
+  TypeParam test_set(test_vals, test_vals + 5);
+  const Matcher<TypeParam> m = ContainerEq(my_set);
+  EXPECT_FALSE(m.Matches(test_set));
+  EXPECT_EQ(
+      "which has these unexpected elements: 46,\n"
+      "and doesn't have these expected elements: 5",
+      Explain(m, test_set));
+}
+
+// Tests duplicated value -- expect no explanation.
+TYPED_TEST(ContainerEqTest, DuplicateDifference) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {1, 2, 3, 5, 8};
+  TypeParam my_set(vals, vals + 6);
+  TypeParam test_set(test_vals, test_vals + 5);
+  const Matcher<const TypeParam&> m = ContainerEq(my_set);
+  // Depending on the container, match may be true or false
+  // But in any case there should be no explanation.
+  EXPECT_EQ("", Explain(m, test_set));
+}
+#endif  // GTEST_HAS_TYPED_TEST
+
+// Tests that multiple missing values are reported.
+// Using just vector here, so order is predictable.
+TEST(ContainerEqExtraTest, MultipleValuesMissing) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {2, 1, 5};
+  vector<int> my_set(vals, vals + 6);
+  vector<int> test_set(test_vals, test_vals + 3);
+  const Matcher<vector<int>> m = ContainerEq(my_set);
+  EXPECT_FALSE(m.Matches(test_set));
+  EXPECT_EQ("which doesn't have these expected elements: 3, 8",
+            Explain(m, test_set));
+}
+
+// Tests that added values are reported.
+// Using just vector here, so order is predictable.
+TEST(ContainerEqExtraTest, MultipleValuesAdded) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {1, 2, 92, 3, 5, 8, 46};
+  list<size_t> my_set(vals, vals + 6);
+  list<size_t> test_set(test_vals, test_vals + 7);
+  const Matcher<const list<size_t>&> m = ContainerEq(my_set);
+  EXPECT_FALSE(m.Matches(test_set));
+  EXPECT_EQ("which has these unexpected elements: 92, 46",
+            Explain(m, test_set));
+}
+
+// Tests that added and missing values are reported together.
+TEST(ContainerEqExtraTest, MultipleValuesAddedAndRemoved) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {1, 2, 3, 92, 46};
+  list<size_t> my_set(vals, vals + 6);
+  list<size_t> test_set(test_vals, test_vals + 5);
+  const Matcher<const list<size_t>> m = ContainerEq(my_set);
+  EXPECT_FALSE(m.Matches(test_set));
+  EXPECT_EQ(
+      "which has these unexpected elements: 92, 46,\n"
+      "and doesn't have these expected elements: 5, 8",
+      Explain(m, test_set));
+}
+
+// Tests to see that duplicate elements are detected,
+// but (as above) not reported in the explanation.
+TEST(ContainerEqExtraTest, MultiSetOfIntDuplicateDifference) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {1, 2, 3, 5, 8};
+  vector<int> my_set(vals, vals + 6);
+  vector<int> test_set(test_vals, test_vals + 5);
+  const Matcher<vector<int>> m = ContainerEq(my_set);
+  EXPECT_TRUE(m.Matches(my_set));
+  EXPECT_FALSE(m.Matches(test_set));
+  // There is nothing to report when both sets contain all the same values.
+  EXPECT_EQ("", Explain(m, test_set));
+}
+
+// Tests that ContainerEq works for non-trivial associative containers,
+// like maps.
+TEST(ContainerEqExtraTest, WorksForMaps) {
+  map<int, std::string> my_map;
+  my_map[0] = "a";
+  my_map[1] = "b";
+
+  map<int, std::string> test_map;
+  test_map[0] = "aa";
+  test_map[1] = "b";
+
+  const Matcher<const map<int, std::string>&> m = ContainerEq(my_map);
+  EXPECT_TRUE(m.Matches(my_map));
+  EXPECT_FALSE(m.Matches(test_map));
+
+  EXPECT_EQ(
+      "which has these unexpected elements: (0, \"aa\"),\n"
+      "and doesn't have these expected elements: (0, \"a\")",
+      Explain(m, test_map));
+}
+
+TEST(ContainerEqExtraTest, WorksForNativeArray) {
+  int a1[] = {1, 2, 3};
+  int a2[] = {1, 2, 3};
+  int b[] = {1, 2, 4};
+
+  EXPECT_THAT(a1, ContainerEq(a2));
+  EXPECT_THAT(a1, Not(ContainerEq(b)));
+}
+
+TEST(ContainerEqExtraTest, WorksForTwoDimensionalNativeArray) {
+  const char a1[][3] = {"hi", "lo"};
+  const char a2[][3] = {"hi", "lo"};
+  const char b[][3] = {"lo", "hi"};
+
+  // Tests using ContainerEq() in the first dimension.
+  EXPECT_THAT(a1, ContainerEq(a2));
+  EXPECT_THAT(a1, Not(ContainerEq(b)));
+
+  // Tests using ContainerEq() in the second dimension.
+  EXPECT_THAT(a1, ElementsAre(ContainerEq(a2[0]), ContainerEq(a2[1])));
+  EXPECT_THAT(a1, ElementsAre(Not(ContainerEq(b[0])), ContainerEq(a2[1])));
+}
+
+TEST(ContainerEqExtraTest, WorksForNativeArrayAsTuple) {
+  const int a1[] = {1, 2, 3};
+  const int a2[] = {1, 2, 3};
+  const int b[] = {1, 2, 3, 4};
+
+  const int* const p1 = a1;
+  EXPECT_THAT(std::make_tuple(p1, 3), ContainerEq(a2));
+  EXPECT_THAT(std::make_tuple(p1, 3), Not(ContainerEq(b)));
+
+  const int c[] = {1, 3, 2};
+  EXPECT_THAT(std::make_tuple(p1, 3), Not(ContainerEq(c)));
+}
+
+TEST(ContainerEqExtraTest, CopiesNativeArrayParameter) {
+  std::string a1[][3] = {{"hi", "hello", "ciao"}, {"bye", "see you", "ciao"}};
+
+  std::string a2[][3] = {{"hi", "hello", "ciao"}, {"bye", "see you", "ciao"}};
+
+  const Matcher<const std::string(&)[2][3]> m = ContainerEq(a2);
+  EXPECT_THAT(a1, m);
+
+  a2[0][0] = "ha";
+  EXPECT_THAT(a1, m);
+}
+
+namespace {
+
+// Used as a check on the more complex max flow method used in the
+// real testing::internal::FindMaxBipartiteMatching. This method is
+// compatible but runs in worst-case factorial time, so we only
+// use it in testing for small problem sizes.
+template <typename Graph>
+class BacktrackingMaxBPMState {
+ public:
+  // Does not take ownership of 'g'.
+  explicit BacktrackingMaxBPMState(const Graph* g) : graph_(g) {}
+
+  ElementMatcherPairs Compute() {
+    if (graph_->LhsSize() == 0 || graph_->RhsSize() == 0) {
+      return best_so_far_;
+    }
+    lhs_used_.assign(graph_->LhsSize(), kUnused);
+    rhs_used_.assign(graph_->RhsSize(), kUnused);
+    for (size_t irhs = 0; irhs < graph_->RhsSize(); ++irhs) {
+      matches_.clear();
+      RecurseInto(irhs);
+      if (best_so_far_.size() == graph_->RhsSize()) break;
+    }
+    return best_so_far_;
+  }
+
+ private:
+  static const size_t kUnused = static_cast<size_t>(-1);
+
+  void PushMatch(size_t lhs, size_t rhs) {
+    matches_.push_back(ElementMatcherPair(lhs, rhs));
+    lhs_used_[lhs] = rhs;
+    rhs_used_[rhs] = lhs;
+    if (matches_.size() > best_so_far_.size()) {
+      best_so_far_ = matches_;
+    }
+  }
+
+  void PopMatch() {
+    const ElementMatcherPair& back = matches_.back();
+    lhs_used_[back.first] = kUnused;
+    rhs_used_[back.second] = kUnused;
+    matches_.pop_back();
+  }
+
+  bool RecurseInto(size_t irhs) {
+    if (rhs_used_[irhs] != kUnused) {
+      return true;
+    }
+    for (size_t ilhs = 0; ilhs < graph_->LhsSize(); ++ilhs) {
+      if (lhs_used_[ilhs] != kUnused) {
+        continue;
+      }
+      if (!graph_->HasEdge(ilhs, irhs)) {
+        continue;
+      }
+      PushMatch(ilhs, irhs);
+      if (best_so_far_.size() == graph_->RhsSize()) {
+        return false;
+      }
+      for (size_t mi = irhs + 1; mi < graph_->RhsSize(); ++mi) {
+        if (!RecurseInto(mi)) return false;
+      }
+      PopMatch();
+    }
+    return true;
+  }
+
+  const Graph* graph_;  // not owned
+  std::vector<size_t> lhs_used_;
+  std::vector<size_t> rhs_used_;
+  ElementMatcherPairs matches_;
+  ElementMatcherPairs best_so_far_;
+};
+
+template <typename Graph>
+const size_t BacktrackingMaxBPMState<Graph>::kUnused;
+
+}  // namespace
+
+// Implement a simple backtracking algorithm to determine if it is possible
+// to find one element per matcher, without reusing elements.
+template <typename Graph>
+ElementMatcherPairs FindBacktrackingMaxBPM(const Graph& g) {
+  return BacktrackingMaxBPMState<Graph>(&g).Compute();
+}
+
+class BacktrackingBPMTest : public ::testing::Test {};
+
+// Tests the MaxBipartiteMatching algorithm with square matrices.
+// The single int param is the # of nodes on each of the left and right sides.
+class BipartiteTest : public ::testing::TestWithParam<size_t> {};
+
+// Verify all match graphs up to some moderate number of edges.
+TEST_P(BipartiteTest, Exhaustive) {
+  size_t nodes = GetParam();
+  MatchMatrix graph(nodes, nodes);
+  do {
+    ElementMatcherPairs matches = internal::FindMaxBipartiteMatching(graph);
+    EXPECT_EQ(FindBacktrackingMaxBPM(graph).size(), matches.size())
+        << "graph: " << graph.DebugString();
+    // Check that all elements of matches are in the graph.
+    // Check that elements of first and second are unique.
+    std::vector<bool> seen_element(graph.LhsSize());
+    std::vector<bool> seen_matcher(graph.RhsSize());
+    SCOPED_TRACE(PrintToString(matches));
+    for (size_t i = 0; i < matches.size(); ++i) {
+      size_t ilhs = matches[i].first;
+      size_t irhs = matches[i].second;
+      EXPECT_TRUE(graph.HasEdge(ilhs, irhs));
+      EXPECT_FALSE(seen_element[ilhs]);
+      EXPECT_FALSE(seen_matcher[irhs]);
+      seen_element[ilhs] = true;
+      seen_matcher[irhs] = true;
+    }
+  } while (graph.NextGraph());
+}
+
+INSTANTIATE_TEST_SUITE_P(AllGraphs, BipartiteTest,
+                         ::testing::Range(size_t{0}, size_t{5}));
+
+// Parameterized by a pair interpreted as (LhsSize, RhsSize).
+class BipartiteNonSquareTest
+    : public ::testing::TestWithParam<std::pair<size_t, size_t>> {};
+
+TEST_F(BipartiteNonSquareTest, SimpleBacktracking) {
+  //   .......
+  // 0:-----\ :
+  // 1:---\ | :
+  // 2:---\ | :
+  // 3:-\ | | :
+  //  :.......:
+  //    0 1 2
+  MatchMatrix g(4, 3);
+  constexpr std::array<std::array<size_t, 2>, 4> kEdges = {
+      {{{0, 2}}, {{1, 1}}, {{2, 1}}, {{3, 0}}}};
+  for (size_t i = 0; i < kEdges.size(); ++i) {
+    g.SetEdge(kEdges[i][0], kEdges[i][1], true);
+  }
+  EXPECT_THAT(FindBacktrackingMaxBPM(g),
+              ElementsAre(Pair(3, 0), Pair(AnyOf(1, 2), 1), Pair(0, 2)))
+      << g.DebugString();
+}
+
+// Verify a few nonsquare matrices.
+TEST_P(BipartiteNonSquareTest, Exhaustive) {
+  size_t nlhs = GetParam().first;
+  size_t nrhs = GetParam().second;
+  MatchMatrix graph(nlhs, nrhs);
+  do {
+    EXPECT_EQ(FindBacktrackingMaxBPM(graph).size(),
+              internal::FindMaxBipartiteMatching(graph).size())
+        << "graph: " << graph.DebugString()
+        << "\nbacktracking: " << PrintToString(FindBacktrackingMaxBPM(graph))
+        << "\nmax flow: "
+        << PrintToString(internal::FindMaxBipartiteMatching(graph));
+  } while (graph.NextGraph());
+}
+
+INSTANTIATE_TEST_SUITE_P(
+    AllGraphs, BipartiteNonSquareTest,
+    testing::Values(std::make_pair(1, 2), std::make_pair(2, 1),
+                    std::make_pair(3, 2), std::make_pair(2, 3),
+                    std::make_pair(4, 1), std::make_pair(1, 4),
+                    std::make_pair(4, 3), std::make_pair(3, 4)));
+
+class BipartiteRandomTest
+    : public ::testing::TestWithParam<std::pair<int, int>> {};
+
+// Verifies a large sample of larger graphs.
+TEST_P(BipartiteRandomTest, LargerNets) {
+  int nodes = GetParam().first;
+  int iters = GetParam().second;
+  MatchMatrix graph(static_cast<size_t>(nodes), static_cast<size_t>(nodes));
+
+  auto seed = static_cast<uint32_t>(GTEST_FLAG_GET(random_seed));
+  if (seed == 0) {
+    seed = static_cast<uint32_t>(time(nullptr));
+  }
+
+  for (; iters > 0; --iters, ++seed) {
+    srand(static_cast<unsigned int>(seed));
+    graph.Randomize();
+    EXPECT_EQ(FindBacktrackingMaxBPM(graph).size(),
+              internal::FindMaxBipartiteMatching(graph).size())
+        << " graph: " << graph.DebugString()
+        << "\nTo reproduce the failure, rerun the test with the flag"
+           " --"
+        << GTEST_FLAG_PREFIX_ << "random_seed=" << seed;
+  }
+}
+
+// Test argument is a std::pair<int, int> representing (nodes, iters).
+INSTANTIATE_TEST_SUITE_P(Samples, BipartiteRandomTest,
+                         testing::Values(std::make_pair(5, 10000),
+                                         std::make_pair(6, 5000),
+                                         std::make_pair(7, 2000),
+                                         std::make_pair(8, 500),
+                                         std::make_pair(9, 100)));
+
+// Tests IsReadableTypeName().
+
+TEST(IsReadableTypeNameTest, ReturnsTrueForShortNames) {
+  EXPECT_TRUE(IsReadableTypeName("int"));
+  EXPECT_TRUE(IsReadableTypeName("const unsigned char*"));
+  EXPECT_TRUE(IsReadableTypeName("MyMap<int, void*>"));
+  EXPECT_TRUE(IsReadableTypeName("void (*)(int, bool)"));
+}
+
+TEST(IsReadableTypeNameTest, ReturnsTrueForLongNonTemplateNonFunctionNames) {
+  EXPECT_TRUE(IsReadableTypeName("my_long_namespace::MyClassName"));
+  EXPECT_TRUE(IsReadableTypeName("int [5][6][7][8][9][10][11]"));
+  EXPECT_TRUE(IsReadableTypeName("my_namespace::MyOuterClass::MyInnerClass"));
+}
+
+TEST(IsReadableTypeNameTest, ReturnsFalseForLongTemplateNames) {
+  EXPECT_FALSE(
+      IsReadableTypeName("basic_string<char, std::char_traits<char> >"));
+  EXPECT_FALSE(IsReadableTypeName("std::vector<int, std::alloc_traits<int> >"));
+}
+
+TEST(IsReadableTypeNameTest, ReturnsFalseForLongFunctionTypeNames) {
+  EXPECT_FALSE(IsReadableTypeName("void (&)(int, bool, char, float)"));
+}
+
+// Tests FormatMatcherDescription().
+
+TEST(FormatMatcherDescriptionTest, WorksForEmptyDescription) {
+  EXPECT_EQ("is even",
+            FormatMatcherDescription(false, "IsEven", {}, Strings()));
+  EXPECT_EQ("not (is even)",
+            FormatMatcherDescription(true, "IsEven", {}, Strings()));
+
+  EXPECT_EQ("equals (a: 5)",
+            FormatMatcherDescription(false, "Equals", {"a"}, {"5"}));
+
+  EXPECT_EQ(
+      "is in range (a: 5, b: 8)",
+      FormatMatcherDescription(false, "IsInRange", {"a", "b"}, {"5", "8"}));
+}
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(MatcherTupleTest);
+
+TEST_P(MatcherTupleTestP, ExplainsMatchFailure) {
+  stringstream ss1;
+  ExplainMatchFailureTupleTo(
+      std::make_tuple(Matcher<char>(Eq('a')), GreaterThan(5)),
+      std::make_tuple('a', 10), &ss1);
+  EXPECT_EQ("", ss1.str());  // Successful match.
+
+  stringstream ss2;
+  ExplainMatchFailureTupleTo(
+      std::make_tuple(GreaterThan(5), Matcher<char>(Eq('a'))),
+      std::make_tuple(2, 'b'), &ss2);
+  EXPECT_EQ(
+      "  Expected arg #0: is > 5\n"
+      "           Actual: 2, which is 3 less than 5\n"
+      "  Expected arg #1: is equal to 'a' (97, 0x61)\n"
+      "           Actual: 'b' (98, 0x62)\n",
+      ss2.str());  // Failed match where both arguments need explanation.
+
+  stringstream ss3;
+  ExplainMatchFailureTupleTo(
+      std::make_tuple(GreaterThan(5), Matcher<char>(Eq('a'))),
+      std::make_tuple(2, 'a'), &ss3);
+  EXPECT_EQ(
+      "  Expected arg #0: is > 5\n"
+      "           Actual: 2, which is 3 less than 5\n",
+      ss3.str());  // Failed match where only one argument needs
+                   // explanation.
+}
+
+#if GTEST_HAS_TYPED_TEST
+
+// Sample optional type implementation with minimal requirements for use with
+// Optional matcher.
+template <typename T>
+class SampleOptional {
+ public:
+  using value_type = T;
+  explicit SampleOptional(T value)
+      : value_(std::move(value)), has_value_(true) {}
+  SampleOptional() : value_(), has_value_(false) {}
+  operator bool() const { return has_value_; }
+  const T& operator*() const { return value_; }
+
+ private:
+  T value_;
+  bool has_value_;
+};
+
+// Sample optional type implementation with alternative minimal requirements for
+// use with Optional matcher. In particular, while it doesn't have a bool
+// conversion operator, it does have a has_value() method.
+template <typename T>
+class SampleOptionalWithoutBoolConversion {
+ public:
+  using value_type = T;
+  explicit SampleOptionalWithoutBoolConversion(T value)
+      : value_(std::move(value)), has_value_(true) {}
+  SampleOptionalWithoutBoolConversion() : value_(), has_value_(false) {}
+  bool has_value() const { return has_value_; }
+  const T& operator*() const { return value_; }
+
+ private:
+  T value_;
+  bool has_value_;
+};
+
+template <typename T>
+class OptionalTest : public testing::Test {};
+
+using OptionalTestTypes =
+    testing::Types<SampleOptional<int>,
+                   SampleOptionalWithoutBoolConversion<int>>;
+
+TYPED_TEST_SUITE(OptionalTest, OptionalTestTypes);
+
+TYPED_TEST(OptionalTest, DescribesSelf) {
+  const Matcher<TypeParam> m = Optional(Eq(1));
+  EXPECT_EQ("value is equal to 1", Describe(m));
+}
+
+TYPED_TEST(OptionalTest, ExplainsSelf) {
+  const Matcher<TypeParam> m = Optional(Eq(1));
+  EXPECT_EQ("whose value 1 matches", Explain(m, TypeParam(1)));
+  EXPECT_EQ("whose value 2 doesn't match", Explain(m, TypeParam(2)));
+}
+
+TYPED_TEST(OptionalTest, MatchesNonEmptyOptional) {
+  const Matcher<TypeParam> m1 = Optional(1);
+  const Matcher<TypeParam> m2 = Optional(Eq(2));
+  const Matcher<TypeParam> m3 = Optional(Lt(3));
+  TypeParam opt(1);
+  EXPECT_TRUE(m1.Matches(opt));
+  EXPECT_FALSE(m2.Matches(opt));
+  EXPECT_TRUE(m3.Matches(opt));
+}
+
+TYPED_TEST(OptionalTest, DoesNotMatchNullopt) {
+  const Matcher<TypeParam> m = Optional(1);
+  TypeParam empty;
+  EXPECT_FALSE(m.Matches(empty));
+}
+
+TYPED_TEST(OptionalTest, ComposesWithMonomorphicMatchersTakingReferences) {
+  const Matcher<const int&> eq1 = Eq(1);
+  const Matcher<const int&> eq2 = Eq(2);
+  TypeParam opt(1);
+  EXPECT_THAT(opt, Optional(eq1));
+  EXPECT_THAT(opt, Optional(Not(eq2)));
+  EXPECT_THAT(opt, Optional(AllOf(eq1, Not(eq2))));
+}
+
+TYPED_TEST(OptionalTest, ComposesWithMonomorphicMatchersRequiringConversion) {
+  const Matcher<int64_t> eq1 = Eq(1);
+  const Matcher<int64_t> eq2 = Eq(2);
+  TypeParam opt(1);
+  EXPECT_THAT(opt, Optional(eq1));
+  EXPECT_THAT(opt, Optional(Not(eq2)));
+  EXPECT_THAT(opt, Optional(AllOf(eq1, Not(eq2))));
+}
+
+template <typename T>
+class MoveOnlyOptionalTest : public testing::Test {};
+
+using MoveOnlyOptionalTestTypes =
+    testing::Types<SampleOptional<std::unique_ptr<int>>,
+                   SampleOptionalWithoutBoolConversion<std::unique_ptr<int>>>;
+
+TYPED_TEST_SUITE(MoveOnlyOptionalTest, MoveOnlyOptionalTestTypes);
+
+TYPED_TEST(MoveOnlyOptionalTest, WorksWithMoveOnly) {
+  Matcher<TypeParam> m = Optional(Eq(nullptr));
+  EXPECT_TRUE(m.Matches(TypeParam(nullptr)));
+}
+
+#endif  // GTEST_HAS_TYPED_TEST
+
+class SampleVariantIntString {
+ public:
+  SampleVariantIntString(int i) : i_(i), has_int_(true) {}
+  SampleVariantIntString(const std::string& s) : s_(s), has_int_(false) {}
+
+  template <typename T>
+  friend bool holds_alternative(const SampleVariantIntString& value) {
+    return value.has_int_ == std::is_same<T, int>::value;
+  }
+
+  template <typename T>
+  friend const T& get(const SampleVariantIntString& value) {
+    return value.get_impl(static_cast<T*>(nullptr));
+  }
+
+ private:
+  const int& get_impl(int*) const { return i_; }
+  const std::string& get_impl(std::string*) const { return s_; }
+
+  int i_;
+  std::string s_;
+  bool has_int_;
+};
+
+TEST(VariantTest, DescribesSelf) {
+  const Matcher<SampleVariantIntString> m = VariantWith<int>(Eq(1));
+  EXPECT_THAT(Describe(m), ContainsRegex("is a variant<> with value of type "
+                                         "'.*' and the value is equal to 1"));
+}
+
+TEST(VariantTest, ExplainsSelf) {
+  const Matcher<SampleVariantIntString> m = VariantWith<int>(Eq(1));
+  EXPECT_THAT(Explain(m, SampleVariantIntString(1)),
+              ContainsRegex("whose value 1"));
+  EXPECT_THAT(Explain(m, SampleVariantIntString("A")),
+              HasSubstr("whose value is not of type '"));
+  EXPECT_THAT(Explain(m, SampleVariantIntString(2)),
+              "whose value 2 doesn't match");
+}
+
+TEST(VariantTest, FullMatch) {
+  Matcher<SampleVariantIntString> m = VariantWith<int>(Eq(1));
+  EXPECT_TRUE(m.Matches(SampleVariantIntString(1)));
+
+  m = VariantWith<std::string>(Eq("1"));
+  EXPECT_TRUE(m.Matches(SampleVariantIntString("1")));
+}
+
+TEST(VariantTest, TypeDoesNotMatch) {
+  Matcher<SampleVariantIntString> m = VariantWith<int>(Eq(1));
+  EXPECT_FALSE(m.Matches(SampleVariantIntString("1")));
+
+  m = VariantWith<std::string>(Eq("1"));
+  EXPECT_FALSE(m.Matches(SampleVariantIntString(1)));
+}
+
+TEST(VariantTest, InnerDoesNotMatch) {
+  Matcher<SampleVariantIntString> m = VariantWith<int>(Eq(1));
+  EXPECT_FALSE(m.Matches(SampleVariantIntString(2)));
+
+  m = VariantWith<std::string>(Eq("1"));
+  EXPECT_FALSE(m.Matches(SampleVariantIntString("2")));
+}
+
+class SampleAnyType {
+ public:
+  explicit SampleAnyType(int i) : index_(0), i_(i) {}
+  explicit SampleAnyType(const std::string& s) : index_(1), s_(s) {}
+
+  template <typename T>
+  friend const T* any_cast(const SampleAnyType* any) {
+    return any->get_impl(static_cast<T*>(nullptr));
+  }
+
+ private:
+  int index_;
+  int i_;
+  std::string s_;
+
+  const int* get_impl(int*) const { return index_ == 0 ? &i_ : nullptr; }
+  const std::string* get_impl(std::string*) const {
+    return index_ == 1 ? &s_ : nullptr;
+  }
+};
+
+TEST(AnyWithTest, FullMatch) {
+  Matcher<SampleAnyType> m = AnyWith<int>(Eq(1));
+  EXPECT_TRUE(m.Matches(SampleAnyType(1)));
+}
+
+TEST(AnyWithTest, TestBadCastType) {
+  Matcher<SampleAnyType> m = AnyWith<std::string>(Eq("fail"));
+  EXPECT_FALSE(m.Matches(SampleAnyType(1)));
+}
+
+TEST(AnyWithTest, TestUseInContainers) {
+  std::vector<SampleAnyType> a;
+  a.emplace_back(1);
+  a.emplace_back(2);
+  a.emplace_back(3);
+  EXPECT_THAT(
+      a, ElementsAreArray({AnyWith<int>(1), AnyWith<int>(2), AnyWith<int>(3)}));
+
+  std::vector<SampleAnyType> b;
+  b.emplace_back("hello");
+  b.emplace_back("merhaba");
+  b.emplace_back("salut");
+  EXPECT_THAT(b, ElementsAreArray({AnyWith<std::string>("hello"),
+                                   AnyWith<std::string>("merhaba"),
+                                   AnyWith<std::string>("salut")}));
+}
+TEST(AnyWithTest, TestCompare) {
+  EXPECT_THAT(SampleAnyType(1), AnyWith<int>(Gt(0)));
+}
+
+TEST(AnyWithTest, DescribesSelf) {
+  const Matcher<const SampleAnyType&> m = AnyWith<int>(Eq(1));
+  EXPECT_THAT(Describe(m), ContainsRegex("is an 'any' type with value of type "
+                                         "'.*' and the value is equal to 1"));
+}
+
+TEST(AnyWithTest, ExplainsSelf) {
+  const Matcher<const SampleAnyType&> m = AnyWith<int>(Eq(1));
+
+  EXPECT_THAT(Explain(m, SampleAnyType(1)), ContainsRegex("whose value 1"));
+  EXPECT_THAT(Explain(m, SampleAnyType("A")),
+              HasSubstr("whose value is not of type '"));
+  EXPECT_THAT(Explain(m, SampleAnyType(2)), "whose value 2 doesn't match");
+}
+
+// Tests Args<k0, ..., kn>(m).
+
+TEST(ArgsTest, AcceptsZeroTemplateArg) {
+  const std::tuple<int, bool> t(5, true);
+  EXPECT_THAT(t, Args<>(Eq(std::tuple<>())));
+  EXPECT_THAT(t, Not(Args<>(Ne(std::tuple<>()))));
+}
+
+TEST(ArgsTest, AcceptsOneTemplateArg) {
+  const std::tuple<int, bool> t(5, true);
+  EXPECT_THAT(t, Args<0>(Eq(std::make_tuple(5))));
+  EXPECT_THAT(t, Args<1>(Eq(std::make_tuple(true))));
+  EXPECT_THAT(t, Not(Args<1>(Eq(std::make_tuple(false)))));
+}
+
+TEST(ArgsTest, AcceptsTwoTemplateArgs) {
+  const std::tuple<short, int, long> t(short{4}, 5, 6L);  // NOLINT
+
+  EXPECT_THAT(t, (Args<0, 1>(Lt())));
+  EXPECT_THAT(t, (Args<1, 2>(Lt())));
+  EXPECT_THAT(t, Not(Args<0, 2>(Gt())));
+}
+
+TEST(ArgsTest, AcceptsRepeatedTemplateArgs) {
+  const std::tuple<short, int, long> t(short{4}, 5, 6L);  // NOLINT
+  EXPECT_THAT(t, (Args<0, 0>(Eq())));
+  EXPECT_THAT(t, Not(Args<1, 1>(Ne())));
+}
+
+TEST(ArgsTest, AcceptsDecreasingTemplateArgs) {
+  const std::tuple<short, int, long> t(short{4}, 5, 6L);  // NOLINT
+  EXPECT_THAT(t, (Args<2, 0>(Gt())));
+  EXPECT_THAT(t, Not(Args<2, 1>(Lt())));
+}
+
+MATCHER(SumIsZero, "") {
+  return std::get<0>(arg) + std::get<1>(arg) + std::get<2>(arg) == 0;
+}
+
+TEST(ArgsTest, AcceptsMoreTemplateArgsThanArityOfOriginalTuple) {
+  EXPECT_THAT(std::make_tuple(-1, 2), (Args<0, 0, 1>(SumIsZero())));
+  EXPECT_THAT(std::make_tuple(1, 2), Not(Args<0, 0, 1>(SumIsZero())));
+}
+
+TEST(ArgsTest, CanBeNested) {
+  const std::tuple<short, int, long, int> t(short{4}, 5, 6L, 6);  // NOLINT
+  EXPECT_THAT(t, (Args<1, 2, 3>(Args<1, 2>(Eq()))));
+  EXPECT_THAT(t, (Args<0, 1, 3>(Args<0, 2>(Lt()))));
+}
+
+TEST(ArgsTest, CanMatchTupleByValue) {
+  typedef std::tuple<char, int, int> Tuple3;
+  const Matcher<Tuple3> m = Args<1, 2>(Lt());
+  EXPECT_TRUE(m.Matches(Tuple3('a', 1, 2)));
+  EXPECT_FALSE(m.Matches(Tuple3('b', 2, 2)));
+}
+
+TEST(ArgsTest, CanMatchTupleByReference) {
+  typedef std::tuple<char, char, int> Tuple3;
+  const Matcher<const Tuple3&> m = Args<0, 1>(Lt());
+  EXPECT_TRUE(m.Matches(Tuple3('a', 'b', 2)));
+  EXPECT_FALSE(m.Matches(Tuple3('b', 'b', 2)));
+}
+
+// Validates that arg is printed as str.
+MATCHER_P(PrintsAs, str, "") { return testing::PrintToString(arg) == str; }
+
+TEST(ArgsTest, AcceptsTenTemplateArgs) {
+  EXPECT_THAT(std::make_tuple(0, 1L, 2, 3L, 4, 5, 6, 7, 8, 9),
+              (Args<9, 8, 7, 6, 5, 4, 3, 2, 1, 0>(
+                  PrintsAs("(9, 8, 7, 6, 5, 4, 3, 2, 1, 0)"))));
+  EXPECT_THAT(std::make_tuple(0, 1L, 2, 3L, 4, 5, 6, 7, 8, 9),
+              Not(Args<9, 8, 7, 6, 5, 4, 3, 2, 1, 0>(
+                  PrintsAs("(0, 8, 7, 6, 5, 4, 3, 2, 1, 0)"))));
+}
+
+TEST(ArgsTest, DescirbesSelfCorrectly) {
+  const Matcher<std::tuple<int, bool, char>> m = Args<2, 0>(Lt());
+  EXPECT_EQ(
+      "are a tuple whose fields (#2, #0) are a pair where "
+      "the first < the second",
+      Describe(m));
+}
+
+TEST(ArgsTest, DescirbesNestedArgsCorrectly) {
+  const Matcher<const std::tuple<int, bool, char, int>&> m =
+      Args<0, 2, 3>(Args<2, 0>(Lt()));
+  EXPECT_EQ(
+      "are a tuple whose fields (#0, #2, #3) are a tuple "
+      "whose fields (#2, #0) are a pair where the first < the second",
+      Describe(m));
+}
+
+TEST(ArgsTest, DescribesNegationCorrectly) {
+  const Matcher<std::tuple<int, char>> m = Args<1, 0>(Gt());
+  EXPECT_EQ(
+      "are a tuple whose fields (#1, #0) aren't a pair "
+      "where the first > the second",
+      DescribeNegation(m));
+}
+
+TEST(ArgsTest, ExplainsMatchResultWithoutInnerExplanation) {
+  const Matcher<std::tuple<bool, int, int>> m = Args<1, 2>(Eq());
+  EXPECT_EQ("whose fields (#1, #2) are (42, 42)",
+            Explain(m, std::make_tuple(false, 42, 42)));
+  EXPECT_EQ("whose fields (#1, #2) are (42, 43)",
+            Explain(m, std::make_tuple(false, 42, 43)));
+}
+
+// For testing Args<>'s explanation.
+class LessThanMatcher : public MatcherInterface<std::tuple<char, int>> {
+ public:
+  void DescribeTo(::std::ostream* /*os*/) const override {}
+
+  bool MatchAndExplain(std::tuple<char, int> value,
+                       MatchResultListener* listener) const override {
+    const int diff = std::get<0>(value) - std::get<1>(value);
+    if (diff > 0) {
+      *listener << "where the first value is " << diff
+                << " more than the second";
+    }
+    return diff < 0;
+  }
+};
+
+Matcher<std::tuple<char, int>> LessThan() {
+  return MakeMatcher(new LessThanMatcher);
+}
+
+TEST(ArgsTest, ExplainsMatchResultWithInnerExplanation) {
+  const Matcher<std::tuple<char, int, int>> m = Args<0, 2>(LessThan());
+  EXPECT_EQ(
+      "whose fields (#0, #2) are ('a' (97, 0x61), 42), "
+      "where the first value is 55 more than the second",
+      Explain(m, std::make_tuple('a', 42, 42)));
+  EXPECT_EQ("whose fields (#0, #2) are ('\\0', 43)",
+            Explain(m, std::make_tuple('\0', 42, 43)));
+}
+
+// Tests for the MATCHER*() macro family.
+
+// Tests that a simple MATCHER() definition works.
+
+MATCHER(IsEven, "") { return (arg % 2) == 0; }
+
+TEST(MatcherMacroTest, Works) {
+  const Matcher<int> m = IsEven();
+  EXPECT_TRUE(m.Matches(6));
+  EXPECT_FALSE(m.Matches(7));
+
+  EXPECT_EQ("is even", Describe(m));
+  EXPECT_EQ("not (is even)", DescribeNegation(m));
+  EXPECT_EQ("", Explain(m, 6));
+  EXPECT_EQ("", Explain(m, 7));
+}
+
+// This also tests that the description string can reference 'negation'.
+MATCHER(IsEven2, negation ? "is odd" : "is even") {
+  if ((arg % 2) == 0) {
+    // Verifies that we can stream to result_listener, a listener
+    // supplied by the MATCHER macro implicitly.
+    *result_listener << "OK";
+    return true;
+  } else {
+    *result_listener << "% 2 == " << (arg % 2);
+    return false;
+  }
+}
+
+// This also tests that the description string can reference matcher
+// parameters.
+MATCHER_P2(EqSumOf, x, y,
+           std::string(negation ? "doesn't equal" : "equals") + " the sum of " +
+               PrintToString(x) + " and " + PrintToString(y)) {
+  if (arg == (x + y)) {
+    *result_listener << "OK";
+    return true;
+  } else {
+    // Verifies that we can stream to the underlying stream of
+    // result_listener.
+    if (result_listener->stream() != nullptr) {
+      *result_listener->stream() << "diff == " << (x + y - arg);
+    }
+    return false;
+  }
+}
+
+// Tests that the matcher description can reference 'negation' and the
+// matcher parameters.
+TEST(MatcherMacroTest, DescriptionCanReferenceNegationAndParameters) {
+  const Matcher<int> m1 = IsEven2();
+  EXPECT_EQ("is even", Describe(m1));
+  EXPECT_EQ("is odd", DescribeNegation(m1));
+
+  const Matcher<int> m2 = EqSumOf(5, 9);
+  EXPECT_EQ("equals the sum of 5 and 9", Describe(m2));
+  EXPECT_EQ("doesn't equal the sum of 5 and 9", DescribeNegation(m2));
+}
+
+// Tests explaining match result in a MATCHER* macro.
+TEST(MatcherMacroTest, CanExplainMatchResult) {
+  const Matcher<int> m1 = IsEven2();
+  EXPECT_EQ("OK", Explain(m1, 4));
+  EXPECT_EQ("% 2 == 1", Explain(m1, 5));
+
+  const Matcher<int> m2 = EqSumOf(1, 2);
+  EXPECT_EQ("OK", Explain(m2, 3));
+  EXPECT_EQ("diff == -1", Explain(m2, 4));
+}
+
+// Tests that the body of MATCHER() can reference the type of the
+// value being matched.
+
+MATCHER(IsEmptyString, "") {
+  StaticAssertTypeEq<::std::string, arg_type>();
+  return arg.empty();
+}
+
+MATCHER(IsEmptyStringByRef, "") {
+  StaticAssertTypeEq<const ::std::string&, arg_type>();
+  return arg.empty();
+}
+
+TEST(MatcherMacroTest, CanReferenceArgType) {
+  const Matcher<::std::string> m1 = IsEmptyString();
+  EXPECT_TRUE(m1.Matches(""));
+
+  const Matcher<const ::std::string&> m2 = IsEmptyStringByRef();
+  EXPECT_TRUE(m2.Matches(""));
+}
+
+// Tests that MATCHER() can be used in a namespace.
+
+namespace matcher_test {
+MATCHER(IsOdd, "") { return (arg % 2) != 0; }
+}  // namespace matcher_test
+
+TEST(MatcherMacroTest, WorksInNamespace) {
+  Matcher<int> m = matcher_test::IsOdd();
+  EXPECT_FALSE(m.Matches(4));
+  EXPECT_TRUE(m.Matches(5));
+}
+
+// Tests that Value() can be used to compose matchers.
+MATCHER(IsPositiveOdd, "") {
+  return Value(arg, matcher_test::IsOdd()) && arg > 0;
+}
+
+TEST(MatcherMacroTest, CanBeComposedUsingValue) {
+  EXPECT_THAT(3, IsPositiveOdd());
+  EXPECT_THAT(4, Not(IsPositiveOdd()));
+  EXPECT_THAT(-1, Not(IsPositiveOdd()));
+}
+
+// Tests that a simple MATCHER_P() definition works.
+
+MATCHER_P(IsGreaterThan32And, n, "") { return arg > 32 && arg > n; }
+
+TEST(MatcherPMacroTest, Works) {
+  const Matcher<int> m = IsGreaterThan32And(5);
+  EXPECT_TRUE(m.Matches(36));
+  EXPECT_FALSE(m.Matches(5));
+
+  EXPECT_EQ("is greater than 32 and (n: 5)", Describe(m));
+  EXPECT_EQ("not (is greater than 32 and (n: 5))", DescribeNegation(m));
+  EXPECT_EQ("", Explain(m, 36));
+  EXPECT_EQ("", Explain(m, 5));
+}
+
+// Tests that the description is calculated correctly from the matcher name.
+MATCHER_P(_is_Greater_Than32and_, n, "") { return arg > 32 && arg > n; }
+
+TEST(MatcherPMacroTest, GeneratesCorrectDescription) {
+  const Matcher<int> m = _is_Greater_Than32and_(5);
+
+  EXPECT_EQ("is greater than 32 and (n: 5)", Describe(m));
+  EXPECT_EQ("not (is greater than 32 and (n: 5))", DescribeNegation(m));
+  EXPECT_EQ("", Explain(m, 36));
+  EXPECT_EQ("", Explain(m, 5));
+}
+
+// Tests that a MATCHER_P matcher can be explicitly instantiated with
+// a reference parameter type.
+
+class UncopyableFoo {
+ public:
+  explicit UncopyableFoo(char value) : value_(value) { (void)value_; }
+
+  UncopyableFoo(const UncopyableFoo&) = delete;
+  void operator=(const UncopyableFoo&) = delete;
+
+ private:
+  char value_;
+};
+
+MATCHER_P(ReferencesUncopyable, variable, "") { return &arg == &variable; }
+
+TEST(MatcherPMacroTest, WorksWhenExplicitlyInstantiatedWithReference) {
+  UncopyableFoo foo1('1'), foo2('2');
+  const Matcher<const UncopyableFoo&> m =
+      ReferencesUncopyable<const UncopyableFoo&>(foo1);
+
+  EXPECT_TRUE(m.Matches(foo1));
+  EXPECT_FALSE(m.Matches(foo2));
+
+  // We don't want the address of the parameter printed, as most
+  // likely it will just annoy the user.  If the address is
+  // interesting, the user should consider passing the parameter by
+  // pointer instead.
+  EXPECT_EQ("references uncopyable (variable: 1-byte object <31>)",
+            Describe(m));
+}
+
+// Tests that the body of MATCHER_Pn() can reference the parameter
+// types.
+
+MATCHER_P3(ParamTypesAreIntLongAndChar, foo, bar, baz, "") {
+  StaticAssertTypeEq<int, foo_type>();
+  StaticAssertTypeEq<long, bar_type>();  // NOLINT
+  StaticAssertTypeEq<char, baz_type>();
+  return arg == 0;
+}
+
+TEST(MatcherPnMacroTest, CanReferenceParamTypes) {
+  EXPECT_THAT(0, ParamTypesAreIntLongAndChar(10, 20L, 'a'));
+}
+
+// Tests that a MATCHER_Pn matcher can be explicitly instantiated with
+// reference parameter types.
+
+MATCHER_P2(ReferencesAnyOf, variable1, variable2, "") {
+  return &arg == &variable1 || &arg == &variable2;
+}
+
+TEST(MatcherPnMacroTest, WorksWhenExplicitlyInstantiatedWithReferences) {
+  UncopyableFoo foo1('1'), foo2('2'), foo3('3');
+  const Matcher<const UncopyableFoo&> const_m =
+      ReferencesAnyOf<const UncopyableFoo&, const UncopyableFoo&>(foo1, foo2);
+
+  EXPECT_TRUE(const_m.Matches(foo1));
+  EXPECT_TRUE(const_m.Matches(foo2));
+  EXPECT_FALSE(const_m.Matches(foo3));
+
+  const Matcher<UncopyableFoo&> m =
+      ReferencesAnyOf<UncopyableFoo&, UncopyableFoo&>(foo1, foo2);
+
+  EXPECT_TRUE(m.Matches(foo1));
+  EXPECT_TRUE(m.Matches(foo2));
+  EXPECT_FALSE(m.Matches(foo3));
+}
+
+TEST(MatcherPnMacroTest,
+     GeneratesCorretDescriptionWhenExplicitlyInstantiatedWithReferences) {
+  UncopyableFoo foo1('1'), foo2('2');
+  const Matcher<const UncopyableFoo&> m =
+      ReferencesAnyOf<const UncopyableFoo&, const UncopyableFoo&>(foo1, foo2);
+
+  // We don't want the addresses of the parameters printed, as most
+  // likely they will just annoy the user.  If the addresses are
+  // interesting, the user should consider passing the parameters by
+  // pointers instead.
+  EXPECT_EQ(
+      "references any of (variable1: 1-byte object <31>, variable2: 1-byte "
+      "object <32>)",
+      Describe(m));
+}
+
+// Tests that a simple MATCHER_P2() definition works.
+
+MATCHER_P2(IsNotInClosedRange, low, hi, "") { return arg < low || arg > hi; }
+
+TEST(MatcherPnMacroTest, Works) {
+  const Matcher<const long&> m = IsNotInClosedRange(10, 20);  // NOLINT
+  EXPECT_TRUE(m.Matches(36L));
+  EXPECT_FALSE(m.Matches(15L));
+
+  EXPECT_EQ("is not in closed range (low: 10, hi: 20)", Describe(m));
+  EXPECT_EQ("not (is not in closed range (low: 10, hi: 20))",
+            DescribeNegation(m));
+  EXPECT_EQ("", Explain(m, 36L));
+  EXPECT_EQ("", Explain(m, 15L));
+}
+
+// Tests that MATCHER*() definitions can be overloaded on the number
+// of parameters; also tests MATCHER_Pn() where n >= 3.
+
+MATCHER(EqualsSumOf, "") { return arg == 0; }
+MATCHER_P(EqualsSumOf, a, "") { return arg == a; }
+MATCHER_P2(EqualsSumOf, a, b, "") { return arg == a + b; }
+MATCHER_P3(EqualsSumOf, a, b, c, "") { return arg == a + b + c; }
+MATCHER_P4(EqualsSumOf, a, b, c, d, "") { return arg == a + b + c + d; }
+MATCHER_P5(EqualsSumOf, a, b, c, d, e, "") { return arg == a + b + c + d + e; }
+MATCHER_P6(EqualsSumOf, a, b, c, d, e, f, "") {
+  return arg == a + b + c + d + e + f;
+}
+MATCHER_P7(EqualsSumOf, a, b, c, d, e, f, g, "") {
+  return arg == a + b + c + d + e + f + g;
+}
+MATCHER_P8(EqualsSumOf, a, b, c, d, e, f, g, h, "") {
+  return arg == a + b + c + d + e + f + g + h;
+}
+MATCHER_P9(EqualsSumOf, a, b, c, d, e, f, g, h, i, "") {
+  return arg == a + b + c + d + e + f + g + h + i;
+}
+MATCHER_P10(EqualsSumOf, a, b, c, d, e, f, g, h, i, j, "") {
+  return arg == a + b + c + d + e + f + g + h + i + j;
+}
+
+TEST(MatcherPnMacroTest, CanBeOverloadedOnNumberOfParameters) {
+  EXPECT_THAT(0, EqualsSumOf());
+  EXPECT_THAT(1, EqualsSumOf(1));
+  EXPECT_THAT(12, EqualsSumOf(10, 2));
+  EXPECT_THAT(123, EqualsSumOf(100, 20, 3));
+  EXPECT_THAT(1234, EqualsSumOf(1000, 200, 30, 4));
+  EXPECT_THAT(12345, EqualsSumOf(10000, 2000, 300, 40, 5));
+  EXPECT_THAT("abcdef",
+              EqualsSumOf(::std::string("a"), 'b', 'c', "d", "e", 'f'));
+  EXPECT_THAT("abcdefg",
+              EqualsSumOf(::std::string("a"), 'b', 'c', "d", "e", 'f', 'g'));
+  EXPECT_THAT("abcdefgh", EqualsSumOf(::std::string("a"), 'b', 'c', "d", "e",
+                                      'f', 'g', "h"));
+  EXPECT_THAT("abcdefghi", EqualsSumOf(::std::string("a"), 'b', 'c', "d", "e",
+                                       'f', 'g', "h", 'i'));
+  EXPECT_THAT("abcdefghij",
+              EqualsSumOf(::std::string("a"), 'b', 'c', "d", "e", 'f', 'g', "h",
+                          'i', ::std::string("j")));
+
+  EXPECT_THAT(1, Not(EqualsSumOf()));
+  EXPECT_THAT(-1, Not(EqualsSumOf(1)));
+  EXPECT_THAT(-12, Not(EqualsSumOf(10, 2)));
+  EXPECT_THAT(-123, Not(EqualsSumOf(100, 20, 3)));
+  EXPECT_THAT(-1234, Not(EqualsSumOf(1000, 200, 30, 4)));
+  EXPECT_THAT(-12345, Not(EqualsSumOf(10000, 2000, 300, 40, 5)));
+  EXPECT_THAT("abcdef ",
+              Not(EqualsSumOf(::std::string("a"), 'b', 'c', "d", "e", 'f')));
+  EXPECT_THAT("abcdefg ", Not(EqualsSumOf(::std::string("a"), 'b', 'c', "d",
+                                          "e", 'f', 'g')));
+  EXPECT_THAT("abcdefgh ", Not(EqualsSumOf(::std::string("a"), 'b', 'c', "d",
+                                           "e", 'f', 'g', "h")));
+  EXPECT_THAT("abcdefghi ", Not(EqualsSumOf(::std::string("a"), 'b', 'c', "d",
+                                            "e", 'f', 'g', "h", 'i')));
+  EXPECT_THAT("abcdefghij ",
+              Not(EqualsSumOf(::std::string("a"), 'b', 'c', "d", "e", 'f', 'g',
+                              "h", 'i', ::std::string("j"))));
+}
+
+// Tests that a MATCHER_Pn() definition can be instantiated with any
+// compatible parameter types.
+TEST(MatcherPnMacroTest, WorksForDifferentParameterTypes) {
+  EXPECT_THAT(123, EqualsSumOf(100L, 20, static_cast<char>(3)));
+  EXPECT_THAT("abcd", EqualsSumOf(::std::string("a"), "b", 'c', "d"));
+
+  EXPECT_THAT(124, Not(EqualsSumOf(100L, 20, static_cast<char>(3))));
+  EXPECT_THAT("abcde", Not(EqualsSumOf(::std::string("a"), "b", 'c', "d")));
+}
+
+// Tests that the matcher body can promote the parameter types.
+
+MATCHER_P2(EqConcat, prefix, suffix, "") {
+  // The following lines promote the two parameters to desired types.
+  std::string prefix_str(prefix);
+  char suffix_char = static_cast<char>(suffix);
+  return arg == prefix_str + suffix_char;
+}
+
+TEST(MatcherPnMacroTest, SimpleTypePromotion) {
+  Matcher<std::string> no_promo = EqConcat(std::string("foo"), 't');
+  Matcher<const std::string&> promo = EqConcat("foo", static_cast<int>('t'));
+  EXPECT_FALSE(no_promo.Matches("fool"));
+  EXPECT_FALSE(promo.Matches("fool"));
+  EXPECT_TRUE(no_promo.Matches("foot"));
+  EXPECT_TRUE(promo.Matches("foot"));
+}
+
+// Verifies the type of a MATCHER*.
+
+TEST(MatcherPnMacroTest, TypesAreCorrect) {
+  // EqualsSumOf() must be assignable to a EqualsSumOfMatcher variable.
+  EqualsSumOfMatcher a0 = EqualsSumOf();
+
+  // EqualsSumOf(1) must be assignable to a EqualsSumOfMatcherP variable.
+  EqualsSumOfMatcherP<int> a1 = EqualsSumOf(1);
+
+  // EqualsSumOf(p1, ..., pk) must be assignable to a EqualsSumOfMatcherPk
+  // variable, and so on.
+  EqualsSumOfMatcherP2<int, char> a2 = EqualsSumOf(1, '2');
+  EqualsSumOfMatcherP3<int, int, char> a3 = EqualsSumOf(1, 2, '3');
+  EqualsSumOfMatcherP4<int, int, int, char> a4 = EqualsSumOf(1, 2, 3, '4');
+  EqualsSumOfMatcherP5<int, int, int, int, char> a5 =
+      EqualsSumOf(1, 2, 3, 4, '5');
+  EqualsSumOfMatcherP6<int, int, int, int, int, char> a6 =
+      EqualsSumOf(1, 2, 3, 4, 5, '6');
+  EqualsSumOfMatcherP7<int, int, int, int, int, int, char> a7 =
+      EqualsSumOf(1, 2, 3, 4, 5, 6, '7');
+  EqualsSumOfMatcherP8<int, int, int, int, int, int, int, char> a8 =
+      EqualsSumOf(1, 2, 3, 4, 5, 6, 7, '8');
+  EqualsSumOfMatcherP9<int, int, int, int, int, int, int, int, char> a9 =
+      EqualsSumOf(1, 2, 3, 4, 5, 6, 7, 8, '9');
+  EqualsSumOfMatcherP10<int, int, int, int, int, int, int, int, int, char> a10 =
+      EqualsSumOf(1, 2, 3, 4, 5, 6, 7, 8, 9, '0');
+
+  // Avoid "unused variable" warnings.
+  (void)a0;
+  (void)a1;
+  (void)a2;
+  (void)a3;
+  (void)a4;
+  (void)a5;
+  (void)a6;
+  (void)a7;
+  (void)a8;
+  (void)a9;
+  (void)a10;
+}
+
+// Tests that matcher-typed parameters can be used in Value() inside a
+// MATCHER_Pn definition.
+
+// Succeeds if arg matches exactly 2 of the 3 matchers.
+MATCHER_P3(TwoOf, m1, m2, m3, "") {
+  const int count = static_cast<int>(Value(arg, m1)) +
+                    static_cast<int>(Value(arg, m2)) +
+                    static_cast<int>(Value(arg, m3));
+  return count == 2;
+}
+
+TEST(MatcherPnMacroTest, CanUseMatcherTypedParameterInValue) {
+  EXPECT_THAT(42, TwoOf(Gt(0), Lt(50), Eq(10)));
+  EXPECT_THAT(0, Not(TwoOf(Gt(-1), Lt(1), Eq(0))));
+}
+
+// Tests Contains().Times().
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(ContainsTimes);
+
+TEST(ContainsTimes, ListMatchesWhenElementQuantityMatches) {
+  list<int> some_list;
+  some_list.push_back(3);
+  some_list.push_back(1);
+  some_list.push_back(2);
+  some_list.push_back(3);
+  EXPECT_THAT(some_list, Contains(3).Times(2));
+  EXPECT_THAT(some_list, Contains(2).Times(1));
+  EXPECT_THAT(some_list, Contains(Ge(2)).Times(3));
+  EXPECT_THAT(some_list, Contains(Ge(2)).Times(Gt(2)));
+  EXPECT_THAT(some_list, Contains(4).Times(0));
+  EXPECT_THAT(some_list, Contains(_).Times(4));
+  EXPECT_THAT(some_list, Not(Contains(5).Times(1)));
+  EXPECT_THAT(some_list, Contains(5).Times(_));  // Times(_) always matches
+  EXPECT_THAT(some_list, Not(Contains(3).Times(1)));
+  EXPECT_THAT(some_list, Contains(3).Times(Not(1)));
+  EXPECT_THAT(list<int>{}, Not(Contains(_)));
+}
+
+TEST_P(ContainsTimesP, ExplainsMatchResultCorrectly) {
+  const int a[2] = {1, 2};
+  Matcher<const int(&)[2]> m = Contains(2).Times(3);
+  EXPECT_EQ(
+      "whose element #1 matches but whose match quantity of 1 does not match",
+      Explain(m, a));
+
+  m = Contains(3).Times(0);
+  EXPECT_EQ("has no element that matches and whose match quantity of 0 matches",
+            Explain(m, a));
+
+  m = Contains(3).Times(4);
+  EXPECT_EQ(
+      "has no element that matches and whose match quantity of 0 does not "
+      "match",
+      Explain(m, a));
+
+  m = Contains(2).Times(4);
+  EXPECT_EQ(
+      "whose element #1 matches but whose match quantity of 1 does not "
+      "match",
+      Explain(m, a));
+
+  m = Contains(GreaterThan(0)).Times(2);
+  EXPECT_EQ("whose elements (0, 1) match and whose match quantity of 2 matches",
+            Explain(m, a));
+
+  m = Contains(GreaterThan(10)).Times(Gt(1));
+  EXPECT_EQ(
+      "has no element that matches and whose match quantity of 0 does not "
+      "match",
+      Explain(m, a));
+
+  m = Contains(GreaterThan(0)).Times(GreaterThan<size_t>(5));
+  EXPECT_EQ(
+      "whose elements (0, 1) match but whose match quantity of 2 does not "
+      "match, which is 3 less than 5",
+      Explain(m, a));
+}
+
+TEST(ContainsTimes, DescribesItselfCorrectly) {
+  Matcher<vector<int>> m = Contains(1).Times(2);
+  EXPECT_EQ("quantity of elements that match is equal to 1 is equal to 2",
+            Describe(m));
+
+  Matcher<vector<int>> m2 = Not(m);
+  EXPECT_EQ("quantity of elements that match is equal to 1 isn't equal to 2",
+            Describe(m2));
+}
+
+// Tests AllOfArray()
+
+TEST(AllOfArrayTest, BasicForms) {
+  // Iterator
+  std::vector<int> v0{};
+  std::vector<int> v1{1};
+  std::vector<int> v2{2, 3};
+  std::vector<int> v3{4, 4, 4};
+  EXPECT_THAT(0, AllOfArray(v0.begin(), v0.end()));
+  EXPECT_THAT(1, AllOfArray(v1.begin(), v1.end()));
+  EXPECT_THAT(2, Not(AllOfArray(v1.begin(), v1.end())));
+  EXPECT_THAT(3, Not(AllOfArray(v2.begin(), v2.end())));
+  EXPECT_THAT(4, AllOfArray(v3.begin(), v3.end()));
+  // Pointer +  size
+  int ar[6] = {1, 2, 3, 4, 4, 4};
+  EXPECT_THAT(0, AllOfArray(ar, 0));
+  EXPECT_THAT(1, AllOfArray(ar, 1));
+  EXPECT_THAT(2, Not(AllOfArray(ar, 1)));
+  EXPECT_THAT(3, Not(AllOfArray(ar + 1, 3)));
+  EXPECT_THAT(4, AllOfArray(ar + 3, 3));
+  // Array
+  // int ar0[0];  Not usable
+  int ar1[1] = {1};
+  int ar2[2] = {2, 3};
+  int ar3[3] = {4, 4, 4};
+  // EXPECT_THAT(0, Not(AllOfArray(ar0)));  // Cannot work
+  EXPECT_THAT(1, AllOfArray(ar1));
+  EXPECT_THAT(2, Not(AllOfArray(ar1)));
+  EXPECT_THAT(3, Not(AllOfArray(ar2)));
+  EXPECT_THAT(4, AllOfArray(ar3));
+  // Container
+  EXPECT_THAT(0, AllOfArray(v0));
+  EXPECT_THAT(1, AllOfArray(v1));
+  EXPECT_THAT(2, Not(AllOfArray(v1)));
+  EXPECT_THAT(3, Not(AllOfArray(v2)));
+  EXPECT_THAT(4, AllOfArray(v3));
+  // Initializer
+  EXPECT_THAT(0, AllOfArray<int>({}));  // Requires template arg.
+  EXPECT_THAT(1, AllOfArray({1}));
+  EXPECT_THAT(2, Not(AllOfArray({1})));
+  EXPECT_THAT(3, Not(AllOfArray({2, 3})));
+  EXPECT_THAT(4, AllOfArray({4, 4, 4}));
+}
+
+TEST(AllOfArrayTest, Matchers) {
+  // vector
+  std::vector<Matcher<int>> matchers{Ge(1), Lt(2)};
+  EXPECT_THAT(0, Not(AllOfArray(matchers)));
+  EXPECT_THAT(1, AllOfArray(matchers));
+  EXPECT_THAT(2, Not(AllOfArray(matchers)));
+  // initializer_list
+  EXPECT_THAT(0, Not(AllOfArray({Ge(0), Ge(1)})));
+  EXPECT_THAT(1, AllOfArray({Ge(0), Ge(1)}));
+}
+
+INSTANTIATE_GTEST_MATCHER_TEST_P(AnyOfArrayTest);
+
+TEST(AnyOfArrayTest, BasicForms) {
+  // Iterator
+  std::vector<int> v0{};
+  std::vector<int> v1{1};
+  std::vector<int> v2{2, 3};
+  EXPECT_THAT(0, Not(AnyOfArray(v0.begin(), v0.end())));
+  EXPECT_THAT(1, AnyOfArray(v1.begin(), v1.end()));
+  EXPECT_THAT(2, Not(AnyOfArray(v1.begin(), v1.end())));
+  EXPECT_THAT(3, AnyOfArray(v2.begin(), v2.end()));
+  EXPECT_THAT(4, Not(AnyOfArray(v2.begin(), v2.end())));
+  // Pointer +  size
+  int ar[3] = {1, 2, 3};
+  EXPECT_THAT(0, Not(AnyOfArray(ar, 0)));
+  EXPECT_THAT(1, AnyOfArray(ar, 1));
+  EXPECT_THAT(2, Not(AnyOfArray(ar, 1)));
+  EXPECT_THAT(3, AnyOfArray(ar + 1, 2));
+  EXPECT_THAT(4, Not(AnyOfArray(ar + 1, 2)));
+  // Array
+  // int ar0[0];  Not usable
+  int ar1[1] = {1};
+  int ar2[2] = {2, 3};
+  // EXPECT_THAT(0, Not(AnyOfArray(ar0)));  // Cannot work
+  EXPECT_THAT(1, AnyOfArray(ar1));
+  EXPECT_THAT(2, Not(AnyOfArray(ar1)));
+  EXPECT_THAT(3, AnyOfArray(ar2));
+  EXPECT_THAT(4, Not(AnyOfArray(ar2)));
+  // Container
+  EXPECT_THAT(0, Not(AnyOfArray(v0)));
+  EXPECT_THAT(1, AnyOfArray(v1));
+  EXPECT_THAT(2, Not(AnyOfArray(v1)));
+  EXPECT_THAT(3, AnyOfArray(v2));
+  EXPECT_THAT(4, Not(AnyOfArray(v2)));
+  // Initializer
+  EXPECT_THAT(0, Not(AnyOfArray<int>({})));  // Requires template arg.
+  EXPECT_THAT(1, AnyOfArray({1}));
+  EXPECT_THAT(2, Not(AnyOfArray({1})));
+  EXPECT_THAT(3, AnyOfArray({2, 3}));
+  EXPECT_THAT(4, Not(AnyOfArray({2, 3})));
+}
+
+TEST(AnyOfArrayTest, Matchers) {
+  // We negate test AllOfArrayTest.Matchers.
+  // vector
+  std::vector<Matcher<int>> matchers{Lt(1), Ge(2)};
+  EXPECT_THAT(0, AnyOfArray(matchers));
+  EXPECT_THAT(1, Not(AnyOfArray(matchers)));
+  EXPECT_THAT(2, AnyOfArray(matchers));
+  // initializer_list
+  EXPECT_THAT(0, AnyOfArray({Lt(0), Lt(1)}));
+  EXPECT_THAT(1, Not(AllOfArray({Lt(0), Lt(1)})));
+}
+
+TEST_P(AnyOfArrayTestP, ExplainsMatchResultCorrectly) {
+  // AnyOfArray and AllOfArray use the same underlying template-template,
+  // thus it is sufficient to test one here.
+  const std::vector<int> v0{};
+  const std::vector<int> v1{1};
+  const std::vector<int> v2{2, 3};
+  const Matcher<int> m0 = AnyOfArray(v0);
+  const Matcher<int> m1 = AnyOfArray(v1);
+  const Matcher<int> m2 = AnyOfArray(v2);
+  EXPECT_EQ("", Explain(m0, 0));
+  EXPECT_EQ("which matches (is equal to 1)", Explain(m1, 1));
+  EXPECT_EQ("isn't equal to 1", Explain(m1, 2));
+  EXPECT_EQ("which matches (is equal to 3)", Explain(m2, 3));
+  EXPECT_EQ("isn't equal to 2, and isn't equal to 3", Explain(m2, 4));
+  EXPECT_EQ("()", Describe(m0));
+  EXPECT_EQ("(is equal to 1)", Describe(m1));
+  EXPECT_EQ("(is equal to 2) or (is equal to 3)", Describe(m2));
+  EXPECT_EQ("()", DescribeNegation(m0));
+  EXPECT_EQ("(isn't equal to 1)", DescribeNegation(m1));
+  EXPECT_EQ("(isn't equal to 2) and (isn't equal to 3)", DescribeNegation(m2));
+  // Explain with matchers
+  const Matcher<int> g1 = AnyOfArray({GreaterThan(1)});
+  const Matcher<int> g2 = AnyOfArray({GreaterThan(1), GreaterThan(2)});
+  // Explains the first positive match and all prior negative matches...
+  EXPECT_EQ("which is 1 less than 1", Explain(g1, 0));
+  EXPECT_EQ("which is the same as 1", Explain(g1, 1));
+  EXPECT_EQ("which is 1 more than 1", Explain(g1, 2));
+  EXPECT_EQ("which is 1 less than 1, and which is 2 less than 2",
+            Explain(g2, 0));
+  EXPECT_EQ("which is the same as 1, and which is 1 less than 2",
+            Explain(g2, 1));
+  EXPECT_EQ("which is 1 more than 1",  // Only the first
+            Explain(g2, 2));
+}
+
+MATCHER(IsNotNull, "") { return arg != nullptr; }
+
+// Verifies that a matcher defined using MATCHER() can work on
+// move-only types.
+TEST(MatcherMacroTest, WorksOnMoveOnlyType) {
+  std::unique_ptr<int> p(new int(3));
+  EXPECT_THAT(p, IsNotNull());
+  EXPECT_THAT(std::unique_ptr<int>(), Not(IsNotNull()));
+}
+
+MATCHER_P(UniquePointee, pointee, "") { return *arg == pointee; }
+
+// Verifies that a matcher defined using MATCHER_P*() can work on
+// move-only types.
+TEST(MatcherPMacroTest, WorksOnMoveOnlyType) {
+  std::unique_ptr<int> p(new int(3));
+  EXPECT_THAT(p, UniquePointee(3));
+  EXPECT_THAT(p, Not(UniquePointee(2)));
+}
+
+MATCHER(EnsureNoUnusedButMarkedUnusedWarning, "") { return (arg % 2) == 0; }
+
+TEST(MockMethodMockFunctionTest, EnsureNoUnusedButMarkedUnusedWarning) {
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic error "-Wused-but-marked-unused"
+#endif
+  // https://github.com/google/googletest/issues/4055
+  EXPECT_THAT(0, EnsureNoUnusedButMarkedUnusedWarning());
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
+}
+
+#if GTEST_HAS_EXCEPTIONS
+
+// std::function<void()> is used below for compatibility with older copies of
+// GCC. Normally, a raw lambda is all that is needed.
+
+// Test that examples from documentation compile
+TEST(ThrowsTest, Examples) {
+  EXPECT_THAT(
+      std::function<void()>([]() { throw std::runtime_error("message"); }),
+      Throws<std::runtime_error>());
+
+  EXPECT_THAT(
+      std::function<void()>([]() { throw std::runtime_error("message"); }),
+      ThrowsMessage<std::runtime_error>(HasSubstr("message")));
+}
+
+TEST(ThrowsTest, PrintsExceptionWhat) {
+  EXPECT_THAT(
+      std::function<void()>([]() { throw std::runtime_error("ABC123XYZ"); }),
+      ThrowsMessage<std::runtime_error>(HasSubstr("ABC123XYZ")));
+}
+
+TEST(ThrowsTest, DoesNotGenerateDuplicateCatchClauseWarning) {
+  EXPECT_THAT(std::function<void()>([]() { throw std::exception(); }),
+              Throws<std::exception>());
+}
+
+TEST(ThrowsTest, CallableExecutedExactlyOnce) {
+  size_t a = 0;
+
+  EXPECT_THAT(std::function<void()>([&a]() {
+                a++;
+                throw 10;
+              }),
+              Throws<int>());
+  EXPECT_EQ(a, 1u);
+
+  EXPECT_THAT(std::function<void()>([&a]() {
+                a++;
+                throw std::runtime_error("message");
+              }),
+              Throws<std::runtime_error>());
+  EXPECT_EQ(a, 2u);
+
+  EXPECT_THAT(std::function<void()>([&a]() {
+                a++;
+                throw std::runtime_error("message");
+              }),
+              ThrowsMessage<std::runtime_error>(HasSubstr("message")));
+  EXPECT_EQ(a, 3u);
+
+  EXPECT_THAT(std::function<void()>([&a]() {
+                a++;
+                throw std::runtime_error("message");
+              }),
+              Throws<std::runtime_error>(
+                  Property(&std::runtime_error::what, HasSubstr("message"))));
+  EXPECT_EQ(a, 4u);
+}
+
+TEST(ThrowsTest, Describe) {
+  Matcher<std::function<void()>> matcher = Throws<std::runtime_error>();
+  std::stringstream ss;
+  matcher.DescribeTo(&ss);
+  auto explanation = ss.str();
+  EXPECT_THAT(explanation, HasSubstr("std::runtime_error"));
+}
+
+TEST(ThrowsTest, Success) {
+  Matcher<std::function<void()>> matcher = Throws<std::runtime_error>();
+  StringMatchResultListener listener;
+  EXPECT_TRUE(matcher.MatchAndExplain(
+      []() { throw std::runtime_error("error message"); }, &listener));
+  EXPECT_THAT(listener.str(), HasSubstr("std::runtime_error"));
+}
+
+TEST(ThrowsTest, FailWrongType) {
+  Matcher<std::function<void()>> matcher = Throws<std::runtime_error>();
+  StringMatchResultListener listener;
+  EXPECT_FALSE(matcher.MatchAndExplain(
+      []() { throw std::logic_error("error message"); }, &listener));
+  EXPECT_THAT(listener.str(), HasSubstr("std::logic_error"));
+  EXPECT_THAT(listener.str(), HasSubstr("\"error message\""));
+}
+
+TEST(ThrowsTest, FailWrongTypeNonStd) {
+  Matcher<std::function<void()>> matcher = Throws<std::runtime_error>();
+  StringMatchResultListener listener;
+  EXPECT_FALSE(matcher.MatchAndExplain([]() { throw 10; }, &listener));
+  EXPECT_THAT(listener.str(),
+              HasSubstr("throws an exception of an unknown type"));
+}
+
+TEST(ThrowsTest, FailNoThrow) {
+  Matcher<std::function<void()>> matcher = Throws<std::runtime_error>();
+  StringMatchResultListener listener;
+  EXPECT_FALSE(matcher.MatchAndExplain([]() { (void)0; }, &listener));
+  EXPECT_THAT(listener.str(), HasSubstr("does not throw any exception"));
+}
+
+class ThrowsPredicateTest
+    : public TestWithParam<Matcher<std::function<void()>>> {};
+
+TEST_P(ThrowsPredicateTest, Describe) {
+  Matcher<std::function<void()>> matcher = GetParam();
+  std::stringstream ss;
+  matcher.DescribeTo(&ss);
+  auto explanation = ss.str();
+  EXPECT_THAT(explanation, HasSubstr("std::runtime_error"));
+  EXPECT_THAT(explanation, HasSubstr("error message"));
+}
+
+TEST_P(ThrowsPredicateTest, Success) {
+  Matcher<std::function<void()>> matcher = GetParam();
+  StringMatchResultListener listener;
+  EXPECT_TRUE(matcher.MatchAndExplain(
+      []() { throw std::runtime_error("error message"); }, &listener));
+  EXPECT_THAT(listener.str(), HasSubstr("std::runtime_error"));
+}
+
+TEST_P(ThrowsPredicateTest, FailWrongType) {
+  Matcher<std::function<void()>> matcher = GetParam();
+  StringMatchResultListener listener;
+  EXPECT_FALSE(matcher.MatchAndExplain(
+      []() { throw std::logic_error("error message"); }, &listener));
+  EXPECT_THAT(listener.str(), HasSubstr("std::logic_error"));
+  EXPECT_THAT(listener.str(), HasSubstr("\"error message\""));
+}
+
+TEST_P(ThrowsPredicateTest, FailWrongTypeNonStd) {
+  Matcher<std::function<void()>> matcher = GetParam();
+  StringMatchResultListener listener;
+  EXPECT_FALSE(matcher.MatchAndExplain([]() { throw 10; }, &listener));
+  EXPECT_THAT(listener.str(),
+              HasSubstr("throws an exception of an unknown type"));
+}
+
+TEST_P(ThrowsPredicateTest, FailNoThrow) {
+  Matcher<std::function<void()>> matcher = GetParam();
+  StringMatchResultListener listener;
+  EXPECT_FALSE(matcher.MatchAndExplain([]() {}, &listener));
+  EXPECT_THAT(listener.str(), HasSubstr("does not throw any exception"));
+}
+
+INSTANTIATE_TEST_SUITE_P(
+    AllMessagePredicates, ThrowsPredicateTest,
+    Values(Matcher<std::function<void()>>(
+        ThrowsMessage<std::runtime_error>(HasSubstr("error message")))));
+
+// Tests that Throws<E1>(Matcher<E2>{}) compiles even when E2 != const E1&.
+TEST(ThrowsPredicateCompilesTest, ExceptionMatcherAcceptsBroadType) {
+  {
+    Matcher<std::function<void()>> matcher =
+        ThrowsMessage<std::runtime_error>(HasSubstr("error message"));
+    EXPECT_TRUE(
+        matcher.Matches([]() { throw std::runtime_error("error message"); }));
+    EXPECT_FALSE(
+        matcher.Matches([]() { throw std::runtime_error("wrong message"); }));
+  }
+
+  {
+    Matcher<uint64_t> inner = Eq(10);
+    Matcher<std::function<void()>> matcher = Throws<uint32_t>(inner);
+    EXPECT_TRUE(matcher.Matches([]() { throw (uint32_t)10; }));
+    EXPECT_FALSE(matcher.Matches([]() { throw (uint32_t)11; }));
+  }
+}
+
+// Tests that ThrowsMessage("message") is equivalent
+// to ThrowsMessage(Eq<std::string>("message")).
+TEST(ThrowsPredicateCompilesTest, MessageMatcherAcceptsNonMatcher) {
+  Matcher<std::function<void()>> matcher =
+      ThrowsMessage<std::runtime_error>("error message");
+  EXPECT_TRUE(
+      matcher.Matches([]() { throw std::runtime_error("error message"); }));
+  EXPECT_FALSE(matcher.Matches(
+      []() { throw std::runtime_error("wrong error message"); }));
+}
+
+#endif  // GTEST_HAS_EXCEPTIONS
+
+}  // namespace
+}  // namespace gmock_matchers_test
+}  // namespace testing
+
+GTEST_DISABLE_MSC_WARNINGS_POP_()  // 4244 4100

googletest/googlemock/test/gmock-matchers_test.h

+// Copyright 2007, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Google Mock - a framework for writing C++ mock classes.
+//
+// This file tests some commonly used argument matchers.
+
+#ifndef GOOGLEMOCK_TEST_GMOCK_MATCHERS_TEST_H_
+#define GOOGLEMOCK_TEST_GMOCK_MATCHERS_TEST_H_
+
+#include <string.h>
+#include <time.h>
+
+#include <array>
+#include <cstdint>
+#include <deque>
+#include <forward_list>
+#include <functional>
+#include <iostream>
+#include <iterator>
+#include <limits>
+#include <list>
+#include <map>
+#include <memory>
+#include <set>
+#include <sstream>
+#include <string>
+#include <type_traits>
+#include <unordered_map>
+#include <unordered_set>
+#include <utility>
+#include <vector>
+
+#include "gmock/gmock-matchers.h"
+#include "gmock/gmock-more-matchers.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest-spi.h"
+#include "gtest/gtest.h"
+
+namespace testing {
+namespace gmock_matchers_test {
+
+using std::greater;
+using std::less;
+using std::list;
+using std::make_pair;
+using std::map;
+using std::multimap;
+using std::multiset;
+using std::ostream;
+using std::pair;
+using std::set;
+using std::stringstream;
+using std::vector;
+using testing::internal::DummyMatchResultListener;
+using testing::internal::ElementMatcherPair;
+using testing::internal::ElementMatcherPairs;
+using testing::internal::ElementsAreArrayMatcher;
+using testing::internal::ExplainMatchFailureTupleTo;
+using testing::internal::FloatingEqMatcher;
+using testing::internal::FormatMatcherDescription;
+using testing::internal::IsReadableTypeName;
+using testing::internal::MatchMatrix;
+using testing::internal::PredicateFormatterFromMatcher;
+using testing::internal::RE;
+using testing::internal::StreamMatchResultListener;
+using testing::internal::Strings;
+
+// Helper for testing container-valued matchers in mock method context. It is
+// important to test matchers in this context, since it requires additional type
+// deduction beyond what EXPECT_THAT does, thus making it more restrictive.
+struct ContainerHelper {
+  MOCK_METHOD1(Call, void(std::vector<std::unique_ptr<int>>));
+};
+
+// For testing ExplainMatchResultTo().
+template <typename T>
+struct GtestGreaterThanMatcher {
+  using is_gtest_matcher = void;
+
+  void DescribeTo(ostream* os) const { *os << "is > " << rhs; }
+  void DescribeNegationTo(ostream* os) const { *os << "is <= " << rhs; }
+
+  bool MatchAndExplain(T lhs, MatchResultListener* listener) const {
+    if (lhs > rhs) {
+      *listener << "which is " << (lhs - rhs) << " more than " << rhs;
+    } else if (lhs == rhs) {
+      *listener << "which is the same as " << rhs;
+    } else {
+      *listener << "which is " << (rhs - lhs) << " less than " << rhs;
+    }
+
+    return lhs > rhs;
+  }
+
+  T rhs;
+};
+
+template <typename T>
+GtestGreaterThanMatcher<typename std::decay<T>::type> GtestGreaterThan(
+    T&& rhs) {
+  return {rhs};
+}
+
+// As the matcher above, but using the base class with virtual functions.
+template <typename T>
+class GreaterThanMatcher : public MatcherInterface<T> {
+ public:
+  explicit GreaterThanMatcher(T rhs) : impl_{rhs} {}
+
+  void DescribeTo(ostream* os) const override { impl_.DescribeTo(os); }
+  void DescribeNegationTo(ostream* os) const override {
+    impl_.DescribeNegationTo(os);
+  }
+
+  bool MatchAndExplain(T lhs, MatchResultListener* listener) const override {
+    return impl_.MatchAndExplain(lhs, listener);
+  }
+
+ private:
+  const GtestGreaterThanMatcher<T> impl_;
+};
+
+// Names and instantiates a new instance of GTestMatcherTestP.
+#define INSTANTIATE_GTEST_MATCHER_TEST_P(TestSuite)                        \
+  using TestSuite##P = GTestMatcherTestP;                                  \
+  INSTANTIATE_TEST_SUITE_P(MatcherInterface, TestSuite##P, Values(false)); \
+  INSTANTIATE_TEST_SUITE_P(GtestMatcher, TestSuite##P, Values(true))
+
+class GTestMatcherTestP : public testing::TestWithParam<bool> {
+ public:
+  template <typename T>
+  Matcher<T> GreaterThan(T n) {
+    if (use_gtest_matcher_) {
+      return GtestGreaterThan(n);
+    } else {
+      return MakeMatcher(new GreaterThanMatcher<T>(n));
+    }
+  }
+  const bool use_gtest_matcher_ = GetParam();
+};
+
+// Returns the description of the given matcher.
+template <typename T>
+std::string Describe(const Matcher<T>& m) {
+  return DescribeMatcher<T>(m);
+}
+
+// Returns the description of the negation of the given matcher.
+template <typename T>
+std::string DescribeNegation(const Matcher<T>& m) {
+  return DescribeMatcher<T>(m, true);
+}
+
+// Returns the reason why x matches, or doesn't match, m.
+template <typename MatcherType, typename Value>
+std::string Explain(const MatcherType& m, const Value& x) {
+  StringMatchResultListener listener;
+  ExplainMatchResult(m, x, &listener);
+  return listener.str();
+}
+
+}  // namespace gmock_matchers_test
+}  // namespace testing
+
+#endif  // GOOGLEMOCK_TEST_GMOCK_MATCHERS_TEST_H_