Mojo: more idiomatic C++ bindings

mojo/public/cpp/bindings/tests/string_unittest.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "mojo/public/cpp/bindings/string.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace mojo {
+namespace test {
+namespace {

[yzshen1, 2014/05/27 22:16:59]

nit: please remove this empty namespace.

+
+}  // namespace
+
+TEST(StringTest, Null) {
+  String s;
+  EXPECT_TRUE(s.is_null());
+}
+
+TEST(StringTest, Basic) {
+  String s("hello world");
+  EXPECT_EQ(std::string("hello world"), s.get());
+}
+
+TEST(StringTest, Assignment) {
+  String s("hello world");
+  String t = s;  // Makes a copy.
+  EXPECT_FALSE(t.is_null());
+  EXPECT_EQ(std::string("hello world"), t.get());
+  EXPECT_FALSE(s.is_null());
+}
+
+TEST(StringTest, Equality) {
+  String s("hello world");
+  String t("hello world");
+  EXPECT_EQ(s, t);
+  EXPECT_TRUE(s == t);
+  EXPECT_TRUE("hello world" == s);
+  EXPECT_TRUE(s == "hello world");
+  EXPECT_TRUE("not" != s);
+  EXPECT_TRUE(s != "not");
+}
+
+}  // namespace test
+}  // namespace mojo