Adds the IsNull() matcher.

include/gmock/gmock-matchers.h

@@ -621,6 +621,19 @@ GMOCK_IMPLEMENT_COMPARISON_MATCHER_(Ne, !=, "not equal to");
 
 #undef GMOCK_IMPLEMENT_COMPARISON_MATCHER_
 
+// Implements the polymorphic IsNull() matcher, which matches any
+// pointer that is NULL.
+class IsNullMatcher {
+ public:
+  template <typename T>
+  bool Matches(T* p) const { return p == NULL; }
+
+  void DescribeTo(::std::ostream* os) const { *os << "is NULL"; }
+  void DescribeNegationTo(::std::ostream* os) const {
+    *os << "is not NULL";
+  }
+};
+
 // Implements the polymorphic NotNull() matcher, which matches any
 // pointer that is not NULL.
 class NotNullMatcher {
@@ -2319,6 +2332,11 @@ inline internal::NeMatcher<Rhs> Ne(Rhs x) {
   return internal::NeMatcher<Rhs>(x);
 }
 
+// Creates a polymorphic matcher that matches any NULL pointer.
+inline PolymorphicMatcher<internal::IsNullMatcher > IsNull() {
+  return MakePolymorphicMatcher(internal::IsNullMatcher());
+}
+
 // Creates a polymorphic matcher that matches any non-NULL pointer.
 // This is convenient as Not(NULL) doesn't compile (the compiler
 // thinks that that expression is comparing a pointer with an integer).

test/gmock-matchers_test.cc

@@ -78,6 +78,7 @@ using testing::FloatEq;
 using testing::Ge;
 using testing::Gt;
 using testing::HasSubstr;
+using testing::IsNull;
 using testing::Key;
 using testing::Le;
 using testing::Lt;
@@ -685,6 +686,32 @@ TEST(NeTest, CanDescribeSelf) {
   EXPECT_EQ("is not equal to 5", Describe(m));
 }
 
+// Tests that IsNull() matches any NULL pointer of any type.
+TEST(IsNullTest, MatchesNullPointer) {
+  Matcher<int*> m1 = IsNull();
+  int* p1 = NULL;
+  int n = 0;
+  EXPECT_TRUE(m1.Matches(p1));
+  EXPECT_FALSE(m1.Matches(&n));
+
+  Matcher<const char*> m2 = IsNull();
+  const char* p2 = NULL;
+  EXPECT_TRUE(m2.Matches(p2));
+  EXPECT_FALSE(m2.Matches("hi"));
+
+  Matcher<void*> m3 = IsNull();
+  void* p3 = NULL;
+  EXPECT_TRUE(m3.Matches(p3));
+  EXPECT_FALSE(m3.Matches(reinterpret_cast<void*>(0xbeef)));
+}
+
+// Tests that IsNull() describes itself properly.
+TEST(IsNullTest, CanDescribeSelf) {
+  Matcher<int*> m = IsNull();
+  EXPECT_EQ("is NULL", Describe(m));
+  EXPECT_EQ("is not NULL", DescribeNegation(m));
+}
+
 // Tests that NotNull() matches any non-NULL pointer of any type.
 TEST(NotNullTest, MatchesNonNullPointer) {
   Matcher<int*> m1 = NotNull();

test/gmock_link_test.h

@@ -147,6 +147,7 @@ using testing::IgnoreResult;
 using testing::Invoke;
 using testing::InvokeArgument;
 using testing::InvokeWithoutArgs;
+using testing::IsNull;
 using testing::Le;
 using testing::Lt;
 using testing::Matcher;
@@ -491,6 +492,13 @@ TEST(LinkTest, TestMatcherNotNull) {
   ON_CALL(mock, VoidFromString(NotNull())).WillByDefault(Return());
 }
 
+// Tests the linkage of the IsNull matcher.
+TEST(LinkTest, TestMatcherIsNull) {
+  Mock mock;
+
+  ON_CALL(mock, VoidFromString(IsNull())).WillByDefault(Return());
+}
+
 // Tests the linkage of the Ref matcher.
 TEST(LinkTest, TestMatcherRef) {
   Mock mock;