如何将 GTest 与 CMake 一起使用？遵循 Google 指南时的链接问题答案

【问题标题】：How to use GTest with CMake ? Linkage problem when following Google's guide如何将 GTest 与 CMake 一起使用？遵循 Google 指南时的链接问题
【发布时间】：2020-10-20 13:42:03
【问题描述】：

我开始为我的项目使用boost测试，但我需要模拟静态方法，所以我尝试切换到GTest和GMock。

我遵循了来自谷歌的非常清晰的guide，CMakeLists 似乎正在完成它的工作：

CMakeLists.txt

cmake_minimum_required(VERSION 3.15)
project(POC_V4)

set(CMAKE_CXX_STANDARD 14)
set(CMAKE_CXX_STANDARD_REQUIRED TRUE)

# Specifying we are using pthread for UNIX systems.
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${TORCH_CXX_FLAGS} -pthread -Wall")

find_package(OpenCV REQUIRED)
find_package(Torch REQUIRED)

# Package needed for Boost tests
find_package (Boost REQUIRED COMPONENTS unit_test_framework)
include_directories (${Boost_INCLUDE_DIRS})

if(NOT Torch_FOUND)
    message(FATAL_ERROR "Pytorch Not Found!")
endif(NOT Torch_FOUND)

message(STATUS "Pytorch status :")
message(STATUS "    libraries: ${TORCH_LIBRARIES}")
message(STATUS "    Torch Flags: ${TORCH_CXX_FLAGS}")

message(STATUS "OpenCV library status :")
message(STATUS "    version: ${OpenCV_VERSION}")
message(STATUS "    libraries: ${OpenCV_LIBS}")
message(STATUS "    include path: ${OpenCV_INCLUDE_DIRS}")


# -------- GOOGLE TEST ----------
# Download and unpack googletest at configure time
enable_testing()
configure_file(CMakeLists.txt.in googletest-download/CMakeLists.txt)
execute_process(COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}" .
        RESULT_VARIABLE result
        WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/googletest-download )
if(result)
    message(FATAL_ERROR "CMake step for googletest failed: ${result}")
endif()
execute_process(COMMAND ${CMAKE_COMMAND} --build .
        RESULT_VARIABLE result
        WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/googletest-download )
if(result)
    message(FATAL_ERROR "Build step for googletest failed: ${result}")
endif()

# Prevent overriding the parent project's compiler/linker
# settings on Windows
set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)

# Add googletest directly to our build. This defines
# the gtest and gtest_main targets.
add_subdirectory(${CMAKE_CURRENT_BINARY_DIR}/googletest-src
        ${CMAKE_CURRENT_BINARY_DIR}/googletest-build
        EXCLUDE_FROM_ALL)

# The gtest/gtest_main targets carry header search path
# dependencies automatically when using CMake 2.8.11 or
# later. Otherwise we have to add them here ourselves.
if (CMAKE_VERSION VERSION_LESS 2.8.11)
    include_directories("${gtest_SOURCE_DIR}/include")
endif()
# -------------------------------------------------------------------------

# Program executable
add_executable(POC_V4 src/main.cpp <all my other files>)

# Test executable
add_executable(POC_V4_tests test/main.cpp <all my other files>)

target_link_libraries(POC_V4 pthread dl util ${TORCH_LIBRARIES} ${OpenCV_LIBS} )
target_link_libraries (POC_V4_tests gtest pthread dl util ${TORCH_LIBRARIES} ${OpenCV_LIBS} )

输出

-- Pytorch status :
--     libraries: torch;torch_library;/usr/lib/libc10.so
--     Torch Flags: -D_GLIBCXX_USE_CXX11_ABI=0
-- OpenCV library status :
--     version: 4.2.0
--     libraries: opencv_calib3d;opencv_core;opencv_dnn;opencv_features2d;opencv_flann;opencv_gapi;opencv_highgui;opencv_imgcodecs;opencv_imgproc;opencv_ml;opencv_objdetect;opencv_photo;opencv_stitching;opencv_video;opencv_videoio
--     include path: /usr/local/include/opencv4
-- Configuring done
-- Generating done
-- Build files have been written to: /tmp/tmp.1U2MhnhFdi/cmake-build-debug-<projectName>_ubuntu/googletest-download
[ 11%] Performing update step for 'googletest'
Current branch master is up to date.
[ 22%] No configure step for 'googletest'
[ 33%] No build step for 'googletest'
[ 44%] No install step for 'googletest'
[ 55%] No test step for 'googletest'
[ 66%] Completed 'googletest'
[100%] Built target googletest
-- Configuring done
-- Generating done
-- Build files have been written to: /tmp/tmp.1U2MhnhFdi/cmake-build-debug-<projectName>_ubuntu

但是当我编译 POC_V4_tests 目标时，出现以下错误

/usr/bin/ld: CMakeFiles/POC_V4_tests.dir/test/boxTest.cpp.o: in function `testing::AssertionResult testing::internal::CmpHelperEQFailure<int, int>(char const*, char const*, int const&, int const&)':
/tmp/tmp.1U2MhnhFdi/cmake-build-debug-<projectName>_ubuntu/googletest-src/googletest/include/gtest/gtest.h:1528: undefined reference to `testing::internal::EqFailure(char const*, char const*, std::string const&, std::string const&, bool)'
collect2: error: ld returned 1 exit status

我是 C++ 新手，所以我可能错过了一些非常简单的东西。有人可以帮我吗？

编辑：

我创建了一个空项目，它工作正常。添加了不同的依赖，发现问题出在libtorch上！

可能 libtorch 定义了一些与 GTest 同名的宏。我还没有找到哪一个，但我希望我能用last part of google's tutorial 修复它。如果有人有想法找出哪个宏失败了，那将对我有很大帮助！ :D

感谢所有试图帮助我的人，我希望你能继续，直到我们纠正这个问题！

【问题讨论】：

附带说明：您不能直接在 gtest/gmock AFAIK 中模拟静态方法。要模拟的方法必须是给定的要模拟的类的虚拟、非静态方法。
哦.. 那么，你知道我如何在 C++ 中模拟 Singleton 类吗？如果我可以模拟虚拟方法，我可以模拟我的getInstance() 调用的方法，但我不确定这是一个好习惯……我发现this 教程可以满足我的需求。但我需要先让 gtest 工作:)
可能与您系统中安装的gtest 和您自动下载的gtest 冲突？检查您是否安装了 gtest（例如 locate libgtest.so）。检查您编译的 libgtest.so（在您的系统和您下载的系统中）是否具有所需的符号 nm -D -C libgtest.so | grep EqFailure。将签名与您的 gtest 标头中的签名进行比较。
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${TORCH_CXX_FLAGS} -pthread -Wall") 这是一个危险信号
您没有在target_link_libraries 中指定PRIVATE | PUBLIC 说明符

标签： c++ cmake linker googletest

【解决方案1】：

我发现问题不是来自 GTest，而是来自 libtorch，它是用 CXX_ABI 符号编译的。只需在 CMakeLists 顶部添加 add_compile_definitions(_GLIBCXX_USE_CXX11_ABI=0) 即可。

阅读this question 了解详细答案。

【讨论】：