如何将 gtest 与 CMake 链接？

Question

我正在尝试使用CMake 创建gtest 的最小示例，但我不确定如何链接测试。

我已经阅读了 gtest 的README。但是，我不想创建CMakeLists.txt.in，而是想学习如何手动将gtest 添加到我使用CMake 的项目中。

问题

• 我无法通过make tests 编译我的测试文件
• 看来我的测试无法链接gtest

错误信息

Scanning dependencies of target tests
[ 25%] Building CXX object CMakeFiles/tests.dir/tests/main_test.cc.o
/Users/kkweon/temp/gtest_tutorial/tests/main_test.cc:5:1: warning: treating Unicode character as whitespace [-Wunicode-whitespace]
  ::testing::InitGoogleTest(&argc, argv);
^
/Users/kkweon/temp/gtest_tutorial/tests/main_test.cc:5:3: warning: treating Unicode character as whitespace [-Wunicode-whitespace]
  ::testing::InitGoogleTest(&argc, argv);
 ^
/Users/kkweon/temp/gtest_tutorial/tests/main_test.cc:6:1: warning: treating Unicode character as whitespace [-Wunicode-whitespace]
  return RUN_ALL_TESTS();
^
/Users/kkweon/temp/gtest_tutorial/tests/main_test.cc:6:3: warning: treating Unicode character as whitespace [-Wunicode-whitespace]
  return RUN_ALL_TESTS();
 ^
4 warnings generated.
[ 50%] Building CXX object CMakeFiles/tests.dir/tests/add_test.cc.o
[ 75%] Building CXX object CMakeFiles/tests.dir/src/add.cc.o
[100%] Linking CXX executable tests
Undefined symbols for architecture x86_64:
  "testing::InitGoogleTest(int*, char**)", referenced from:
      _main in main_test.cc.o
  "testing::Test::SetUp()", referenced from:
      vtable for AddTest_AddIntegers_Test in add_test.cc.o
  "testing::Test::TearDown()", referenced from:
      vtable for AddTest_AddIntegers_Test in add_test.cc.o
  "testing::Test::Test()", referenced from:
      AddTest_AddIntegers_Test::AddTest_AddIntegers_Test() in add_test.cc.o
  "testing::Test::~Test()", referenced from:
      AddTest_AddIntegers_Test::~AddTest_AddIntegers_Test() in add_test.cc.o
  "testing::Message::Message()", referenced from:
      AddTest_AddIntegers_Test::TestBody() in add_test.cc.o
  "testing::UnitTest::GetInstance()", referenced from:
      RUN_ALL_TESTS() in main_test.cc.o
  "testing::UnitTest::Run()", referenced from:
      RUN_ALL_TESTS() in main_test.cc.o
  "testing::internal::AssertHelper::AssertHelper(testing::TestPartResult::Type, char const*, int, char const*)", referenced from:
      AddTest_AddIntegers_Test::TestBody() in add_test.cc.o
  "testing::internal::AssertHelper::~AssertHelper()", referenced from:
      AddTest_AddIntegers_Test::TestBody() in add_test.cc.o
  "testing::internal::GetTestTypeId()", referenced from:
      ___cxx_global_var_init in add_test.cc.o
  "testing::internal::MakeAndRegisterTestInfo(char const*, char const*, char const*, char const*, testing::internal::CodeLocation, void const*, void (*)(), void (*)(), testing::internal::TestFactoryBase*)", referenced from:
      ___cxx_global_var_init in add_test.cc.o
  "testing::internal::GetBoolAssertionFailureMessage(testing::AssertionResult const&, char const*, char const*, char const*)", referenced from:
      AddTest_AddIntegers_Test::TestBody() in add_test.cc.o
  "testing::internal::IsTrue(bool)", referenced from:
      testing::internal::scoped_ptr<std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char> > >::reset(std::__1::basic_stringstream<char, std::__1::char_traits<char>, std::__1::allocator<char> >*) in add_test.cc.o
      testing::internal::scoped_ptr<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >::reset(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >*) in add_test.cc.o
  "testing::internal::AssertHelper::operator=(testing::Message const&) const", referenced from:
      AddTest_AddIntegers_Test::TestBody() in add_test.cc.o
  "typeinfo for testing::Test", referenced from:
      typeinfo for AddTest_AddIntegers_Test in add_test.cc.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[3]: *** [tests] Error 1
make[2]: *** [CMakeFiles/tests.dir/all] Error 2
make[1]: *** [CMakeFiles/tests.dir/rule] Error 2
make: *** [tests] Error 2

信息

我已经将googletest repository下载到/Users/kkweon/github/googletest

而“gtest.h”位于/Users/kkweon/github/googletest/googletest/include/gtest/gtest.h

我的项目结构：

.
├── CMakeLists.txt
├── src
│   ├── add.cc
│   ├── add.h
│   └── main.cc
└── tests
    ├── add_test.cc
    └── main_test.cc

和 CMakeLists.txt 文件

cmake_minimum_required(VERSION 3.0)

set(EXTRA_BINCFLAGS "-Wall -Wextra")
set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} ${EXTRA_BINCFLAGS})

include_directories(/Users/kkweon/github/googletest/googletest/include)
include_directories(src)

set(SOURCES src/add.cc)
set(TEST_SOURCES tests/main_test.cc tests/add_test.cc)

add_executable(main src/main.cc ${SOURCES})
add_executable(tests ${TEST_SOURCES} ${SOURCES})

完整源代码：github

提前谢谢你！

Answer 1

仅include_directories 与 googletest 是不够的。您还必须添加要编译的源代码。

这是what we do：

我们创建一个单独的 CMake 目标 google-test 将其编译为库。我们将 googletest 文件夹包含到我们的源代码树中，以便我们的项目和 Google 测试保持在一起。

在你的主要CMakeLists 你做add_subdirectory(googletest)

googletest 文件夹有自己的CMakeLists.txt 文件和include/ 和src/ 文件夹（无需存储完整的googletest repo！）。

tree googletest/

googletest/
├── CMakeLists.txt
├── include
│   └── gtest
│       ├── gtest-death-test.h
        ...
└── src
    ├── gtest-all.cc
    ├── gtest.cc
    └── gtest_main.cc
    ...

在你的googletest/CMakeLists.txt 你这样做：

set(google_test_include_dirs
  "${CMAKE_CURRENT_SOURCE_DIR}"
  "${CMAKE_CURRENT_SOURCE_DIR}/include")
include_directories(${google_test_include_dirs})
file(GLOB_RECURSE google_test_headers ${CMAKE_CURRENT_SOURCE_DIR}/*.h)
set(google_test_sources src/gtest-all.cc src/gtest_main.cc)
add_library(google-test STATIC ${google_test_sources} ${google_test_headers})

然后为您的目标进行测试，您可以执行以下操作：

add_executable(MyTests ${my_unittests_sources})
include_directories("${CMAKE_CURRENT_SOURCE_DIR}")
include_directories("${CMAKE_SOURCE_DIR}/googletest/include")

target_link_libraries(MyTests google-test)

请参阅我上面链接的项目中的CMakeLists.txt、googletest/CMakeLists.txt 和unittests/CMakeLists.txt。