libweave: Added gtest_prod_util.h

Cloned from
https://android.googlesource.com/platform/external/libchrome/+/3ca9d0096f5618f5bbad8b1363a069d13fc3026e

It's unchanged.

BUG=brillo:1256
TEST=`FEATURES=test emerge-gizmo libweave buffet`

Change-Id: I6e42142009e44345ec44472322b1267e23f4ee31
Reviewed-on: https://chromium-review.googlesource.com/294341
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
Tested-by: Vitaly Buka <vitalybuka@chromium.org>

libweave/external/base/gtest_prod_util.h

diff --git a/libweave/external/base/gtest_prod_util.h b/libweave/external/base/gtest_prod_util.h
new file mode 100644
index 0000000..3289e63
--- /dev/null
+++ b/libweave/external/base/gtest_prod_util.h
@@ -0,0 +1,66 @@
+// Copyright (c) 2012 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.
+
+#ifndef BASE_GTEST_PROD_UTIL_H_
+#define BASE_GTEST_PROD_UTIL_H_
+
+#include "testing/gtest/include/gtest/gtest_prod.h"
+
+// This is a wrapper for gtest's FRIEND_TEST macro that friends
+// test with all possible prefixes. This is very helpful when changing the test
+// prefix, because the friend declarations don't need to be updated.
+//
+// Example usage:
+//
+// class MyClass {
+//  private:
+//   void MyMethod();
+//   FRIEND_TEST_ALL_PREFIXES(MyClassTest, MyMethod);
+// };
+#define FRIEND_TEST_ALL_PREFIXES(test_case_name, test_name) \
+  FRIEND_TEST(test_case_name, test_name); \
+  FRIEND_TEST(test_case_name, DISABLED_##test_name); \
+  FRIEND_TEST(test_case_name, FLAKY_##test_name)
+
+// C++ compilers will refuse to compile the following code:
+//
+// namespace foo {
+// class MyClass {
+//  private:
+//   FRIEND_TEST_ALL_PREFIXES(MyClassTest, TestMethod);
+//   bool private_var;
+// };
+// }  // namespace foo
+//
+// class MyClassTest::TestMethod() {
+//   foo::MyClass foo_class;
+//   foo_class.private_var = true;
+// }
+//
+// Unless you forward declare MyClassTest::TestMethod outside of namespace foo.
+// Use FORWARD_DECLARE_TEST to do so for all possible prefixes.
+//
+// Example usage:
+//
+// FORWARD_DECLARE_TEST(MyClassTest, TestMethod);
+//
+// namespace foo {
+// class MyClass {
+//  private:
+//   FRIEND_TEST_ALL_PREFIXES(::MyClassTest, TestMethod);  // NOTE use of ::
+//   bool private_var;
+// };
+// }  // namespace foo
+//
+// class MyClassTest::TestMethod() {
+//   foo::MyClass foo_class;
+//   foo_class.private_var = true;
+// }
+
+#define FORWARD_DECLARE_TEST(test_case_name, test_name) \
+  class test_case_name##_##test_name##_Test; \
+  class test_case_name##_##DISABLED_##test_name##_Test; \
+  class test_case_name##_##FLAKY_##test_name##_Test
+
+#endif  // BASE_GTEST_PROD_UTIL_H_