ColdClassTest.cpp

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/*
 * Copyright 2017-present Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <folly/lang/ColdClass.h>

#include <folly/portability/GTest.h>
#include <type_traits>

using folly::ColdClass;

template <class TestClass>
static void validateInheritedClass() {
  // The only verifiable property of ColdClass is that it must not disrupt the
  // default constructor/destructor, default copy/move constructors and default
  // copy/move assignment operators when a class derives from it.
  EXPECT_TRUE(std::is_nothrow_default_constructible<TestClass>::value);
#if !defined(__GLIBCXX__) || __GNUC__ >= 5
  EXPECT_TRUE(std::is_trivially_copy_constructible<TestClass>::value);
  EXPECT_TRUE(std::is_trivially_move_constructible<TestClass>::value);
  EXPECT_TRUE(std::is_trivially_copy_assignable<TestClass>::value);
  EXPECT_TRUE(std::is_trivially_move_assignable<TestClass>::value);
#endif
  EXPECT_TRUE(std::is_nothrow_copy_constructible<TestClass>::value);
  EXPECT_TRUE(std::is_nothrow_move_constructible<TestClass>::value);
  EXPECT_TRUE(std::is_nothrow_copy_assignable<TestClass>::value);
  EXPECT_TRUE(std::is_nothrow_move_assignable<TestClass>::value);
  EXPECT_TRUE(std::is_trivially_destructible<TestClass>::value);
}

TEST(ColdClassTest, publicInheritance) {
  struct TestPublic : ColdClass {};
  validateInheritedClass<TestPublic>();
}

TEST(ColdClassTest, protectedInheritance) {
  // Same again, but protected inheritance. Should make no difference.
  class TestProtected : protected ColdClass {};
  validateInheritedClass<TestProtected>();
}

TEST(ColdClassTest, privateInheritance) {
  // Same again, but private inheritance. Should make no difference.
  class TestPrivate : ColdClass {};
  validateInheritedClass<TestPrivate>();
}