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This is my first post on StackOverflow, so apologies if there's something wrong with my question.

I'm new at CMake, and I'm running into a problem trying to import gtest (Google Test) in a C++ project with an existing gtest directory used within a library.

My root CMakeLists.txt file is this (My changes are made between "Begin changes" and "End changes") :

cmake_minimum_required(VERSION 2.6) project(nifi-minifi-cpp) set(PROJECT_NAME "nifi-minifi-cpp") set(PROJECT_VERSION_MAJOR 0) set(PROJECT_VERSION_MINOR 2) set(PROJECT_VERSION_PATCH 0) #### Establish Project Configuration #### # Enable usage of the VERSION specifier # https://cmake.org/cmake/help/v3.0/policy/CMP0048.html#policy:CMP0048 IF(POLICY CMP0048) CMAKE_POLICY(SET CMP0048 OLD) ENDIF(POLICY CMP0048) include(CheckCXXCompilerFlag) CHECK_CXX_COMPILER_FLAG("-std=c++11" COMPILER_SUPPORTS_CXX11) CHECK_CXX_COMPILER_FLAG("-std=c++0x" COMPILER_SUPPORTS_CXX0X) if(COMPILER_SUPPORTS_CXX11) set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11") elseif(COMPILER_SUPPORTS_CXX0X) set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x") else() message(STATUS "The compiler ${CMAKE_CXX_COMPILER} has no C++11 support. Please use a different C++ compiler.") endif() set(CMAKE_CXX_STANDARD 11) set(CMAKE_CXX_STANDARD_REQUIRED ON) # Search for threads find_package(Threads REQUIRED) # Provide custom modules for the project list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake") add_subdirectory(thirdparty/yaml-cpp-yaml-cpp-0.5.3) add_subdirectory(libminifi) add_subdirectory(main) # Generate source assembly set(ASSEMBLY_BASE_NAME "${CMAKE_PROJECT_NAME}-${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}.${PROJECT_VERSION_PATCH}") set(CPACK_SOURCE_GENERATOR "TGZ") set(CPACK_SOURCE_PACKAGE_FILE_NAME "${ASSEMBLY_BASE_NAME}-source") set(CPACK_SOURCE_IGNORE_FILES "/build/;~$;${CPACK_SOURCE_IGNORE_FILES};${CMAKE_SOURCE_DIR}/.git/;${CMAKE_SOURCE_DIR}/.idea/;${CMAKE_SOURCE_DIR}/cmake-build-debug/") # Generate binary assembly install(FILES conf/minifi.properties conf/config.yml DESTINATION conf COMPONENT bin) install(PROGRAMS bin/minifi.sh DESTINATION bin COMPONENT bin) install(FILES LICENSE README.md NOTICE DESTINATION . COMPONENT bin) set(CPACK_GENERATOR "TGZ") set(CPACK_COMPONENT_INCLUDE_TOPLEVEL_DIRECTORY 1) set(CPACK_PACKAGE_DESCRIPTION_SUMMARY "Apache NiFi MiNiFi C++ version ${VERSION}") set(CPACK_PACKAGE_VENDOR "Apache NiFi") set(CPACK_PACKAGE_DESCRIPTION_FILE "${CMAKE_CURRENT_SOURCE_DIR}/README.md") set(CPACK_RESOURCE_FILE_LICENSE "${CMAKE_CURRENT_SOURCE_DIR}/LICENSE") set(CPACK_PACKAGE_FILE_NAME "${ASSEMBLY_BASE_NAME}") set(CPACK_BINARY_TGZ, "ON") set(CPACK_ARCHIVE_COMPONENT_INSTALL ON) set(CPACK_COMPONENTS_ALL bin) include(CPack) #### Begin changes # Set up testing enable_testing() set(GTEST_ROOT "thirdparty/googletest/googletest") add_subdirectory(thirdparty/googletest) # find_package(GTest REQUIRED) include_directories(${GTEST_INCLUDE_DIRS}) add_executable(tailFileTest test/TailFileTest.cpp ) target_link_libraries(tailFileTest ${GTEST_LIBRARY_DEBUG} ${GTEST_MAIN_LIBRARY_DEBUG}) add_test( NAME tailFileTest COMMAND tailFileTest ) #add_dependencies(${PROJECT_TEST_NAME} googletest) #set(PROJECT_TEST_NAME ${PROJECT_NAME}_test) #file(GLOB TEST_SRC_FILES ${PROJECT_SOURCE_DIR}/test/*.cpp) # #add_executable(${PROJECT_TEST_NAME} ${TEST_SRC_FILES}) #add_dependencies(${PROJECT_TEST_NAME} googletest) #### End changes

And output from CMake when running cmake .. (the more relevant error message - probably) is:

CMake Error at thirdparty/googletest/googletest/cmake/internal_utils.cmake:151 (add_library): add_library cannot create target "gtest" because another target with the same name already exists. The existing target is a static library created in source directory "/home/dev/nifi-minifi-cpp/thirdparty/yaml-cpp-yaml-cpp-0.5.3/test/gmock-1.7.0/gtest". See documentation for policy CMP0002 for more details.

Currently, I've got a copy of googletest in:

/home/g/dev/nifi-minifi-cpp/thirdparty/googletest

And the existing googletest directory is within:

/home/g/dev/nifi-minifi-cpp/thirdparty/yaml-cpp-yaml-cpp-0.5.3/test/gmock-1.7.0

Here's a quick picture of the directory structure:

. ├── CMakeLists.txt ├── test [<- My directory to store and run tests] └── thirdparty ├── googletest [<- My googletest directory] └── yaml-cpp-yaml-cpp-0.5.3 ├── test │   ├── CMakeLists.txt │   ├── gmock-1.7.0 [<- The existing googletest directory] 278 directories, 2096 files

The overall goal is to have a test directory for running tests.

Any suggestions or clues to what I'm doing wrong, or what I should be doing, would be greatly appreciated. Hopefully the above explains the challenge I'm facing, and if there's a file or error message people think I'm missing that would help I can paste it in here.

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  • Why do you have two googleTest folders (My googletest directory and The existing googletest directory) ? Is it possible that you have in the CMakeList from yaml-cpp-yaml-cpp-0.5.3 also a entry add_subdirectory(gmock-1.7.0)? This could be the problem, because of your error message said that you have multiple targets with the name gtest. Commented Feb 7, 2017 at 10:29

1 Answer 1

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3

This is just double including 3d-party project (gtest in your case) using add_subdirectory. The first include point is 

add_subdirectory(gmock-1.7.0)

inside yaml-cpp subproject and the second include point is

add_subdirectory(thirdparty/googletest)

in your CMakeLists.txt.

Such double including doesn't work in CMake, so you need to eliminate one of add_subdirectory call.

  1. In your code, you may replace add_subdirectory approach by combination of ExternalProject_Add and execute_process. That approach will build googletest on configuration stage (so, find_package(GTest) will work), but doesn't pollute namespace of your project with targets from googletest.

  2. In other project (yaml-cpp), you may eliminate including googletest by disable testing. Just disable appropriate option

    option(YAML_CPP_BUILD_TOOLS "Enable testing and parse tools" OFF)

    before

    add_subdirectory(thirdparty/yaml-cpp-yaml-cpp-0.5.3)

    (For disabling option from CMakeLists.txt you need to reconfigure the whole project cleanly, that is with empty CMake cache).

    Note, that this option also disables some utilities under util/ subdirectory of yaml-cpp project.

  3. Similarly to the first approach, you may change inclusion of yaml-cpp subproject to ExternalProject_Add + execute_process. Such a way all its targets and targets of its subprojects will not pollute namespace of your project.

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4 Comments

can you give an example for case 1? Thanks!
Hm, don't remember why ExternalProject is needed in that case. Configure gtest: execute_process(COMMAND ${CMAKE_EXECUTABLE} <gtest-source-dir> -DCMAKE_INSTALL_PREFIX=<choosen-gtest-install-dir> WORKING_DIRECTORY <choosen-gtest-build-dir>). Build and install gtest: execute_process(COMMAND ${CMAKE_EXECUTABLE} --build <choosen-gtest-build-dir> --target install).
@Tsyvarev This, unfortunately, doesn't work. It cannot find the gtest/gtest.h in the tests.
@Patrick: What exact approach doesn't work? What exact commands you use? It is better to create your own question post with all this information.

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