add unit test for overload & operator

googletest/test/googletest-overload-addressof-operator-test.cc

+// Copyright 2008, 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.
+//
+// This file tests EXPECT_EQ works when used with type that has overloaded &
+// operator.
+
+#include <gtest/gtest.h>
+#include <string>
+
+class string_ref;
+
+/**
+ * This is a synthetic pointer to a fixed size string.
+ */
+class string_ptr {
+ public:
+  string_ptr(const char *data, size_t size) : data_(data), size_(size) {}
+
+  string_ptr &operator++() noexcept {
+    data_ += size_;
+    return *this;
+  }
+
+  string_ref operator*() const noexcept;
+
+ private:
+  const char *data_;
+  size_t size_;
+};
+
+/**
+ * This is a synthetic reference of a fixed size string.
+ */
+class string_ref {
+ public:
+  string_ref(const char *data, size_t size) : data_(data), size_(size) {}
+
+  string_ptr operator&() const noexcept { return {data_, size_}; }
+
+  bool operator==(const char *s) const noexcept {
+    if (size_ > 0 && data_[size_ - 1] != 0) {
+      return std::string(data_, size_) == std::string(s);
+    } else {
+      return std::string(data_) == std::string(s);
+    }
+  }
+
+ private:
+  const char *data_;
+  size_t size_;
+};
+
+string_ref string_ptr::operator*() const noexcept { return {data_, size_}; }
+
+TEST(string_ref, compare) {
+  const char *s = "alex\0davidjohn\0";
+  string_ptr ptr(s, 5);
+  EXPECT_EQ(*ptr, "alex");
+  EXPECT_TRUE(*ptr == "alex");
+  ++ptr;
+  EXPECT_EQ(*ptr, "david");
+  EXPECT_TRUE(*ptr == "david");
+  ++ptr;
+  EXPECT_EQ(*ptr, "john");
+}