CMake + GoogleTest

This is an unusual case; most projects specify install rules.

CMake's ExternalProject_Add module is maybe the best tool for this job. This allows you to download, configure and build gtest from within your project, and then link to the gtest libraries.

I've tested the following CMakeLists.txt on Windows with Visual Studio 10 and 11, and on Ubuntu using GCC 4.8 and Clang 3.2 - it might need adjusted for other platforms/compilers:

cmake_minimum_required(VERSION 2.8.7 FATAL_ERROR)
project(Test)

# Create main.cpp which uses gtest
file(WRITE src/main.cpp "#include \"gtest/gtest.h\"\n\n")
file(APPEND src/main.cpp "TEST(A, B) { SUCCEED(); }\n")
file(APPEND src/main.cpp "int main(int argc, char **argv) {\n")
file(APPEND src/main.cpp "  testing::InitGoogleTest(&argc, argv);\n")
file(APPEND src/main.cpp "  return RUN_ALL_TESTS();\n")
file(APPEND src/main.cpp "}\n")

# Create patch file for gtest with MSVC 2012
if(MSVC_VERSION EQUAL 1700)
  file(WRITE gtest.patch "Index: cmake/internal_utils.cmake\n")
  file(APPEND gtest.patch "===================================================================\n")
  file(APPEND gtest.patch "--- cmake/internal_utils.cmake   (revision 660)\n")
  file(APPEND gtest.patch "+++ cmake/internal_utils.cmake   (working copy)\n")
  file(APPEND gtest.patch "@@ -66,6 +66,9 @@\n")
  file(APPEND gtest.patch "       # Resolved overload was found by argument-dependent lookup.\n")
  file(APPEND gtest.patch "       set(cxx_base_flags \"\${cxx_base_flags} -wd4675\")\n")
  file(APPEND gtest.patch "     endif()\n")
  file(APPEND gtest.patch "+    if (MSVC_VERSION EQUAL 1700)\n")
  file(APPEND gtest.patch "+      set(cxx_base_flags \"\${cxx_base_flags} -D_VARIADIC_MAX=10\")\n")
  file(APPEND gtest.patch "+    endif ()\n")
  file(APPEND gtest.patch "     set(cxx_base_flags \"\${cxx_base_flags} -D_UNICODE -DUNICODE -DWIN32 -D_WIN32\")\n")
  file(APPEND gtest.patch "     set(cxx_base_flags \"\${cxx_base_flags} -DSTRICT -DWIN32_LEAN_AND_MEAN\")\n")
  file(APPEND gtest.patch "     set(cxx_exception_flags \"-EHsc -D_HAS_EXCEPTIONS=1\")\n")
else()
  file(WRITE gtest.patch "")
endif()

# Enable ExternalProject CMake module
include(ExternalProject)

# Set the build type if it isn't already
if(NOT CMAKE_BUILD_TYPE)
  set(CMAKE_BUILD_TYPE Release)
endif()

# Set default ExternalProject root directory
set_directory_properties(PROPERTIES EP_PREFIX ${CMAKE_BINARY_DIR}/ThirdParty)

# Add gtest
ExternalProject_Add(
    googletest
    SVN_REPOSITORY http://googletest.googlecode.com/svn/trunk/
    SVN_REVISION -r 660
    TIMEOUT 10
    PATCH_COMMAND svn patch ${CMAKE_SOURCE_DIR}/gtest.patch ${CMAKE_BINARY_DIR}/ThirdParty/src/googletest
    # Force separate output paths for debug and release builds to allow easy
    # identification of correct lib in subsequent TARGET_LINK_LIBRARIES commands
    CMAKE_ARGS -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
               -DCMAKE_ARCHIVE_OUTPUT_DIRECTORY_DEBUG:PATH=DebugLibs
               -DCMAKE_ARCHIVE_OUTPUT_DIRECTORY_RELEASE:PATH=ReleaseLibs
               -Dgtest_force_shared_crt=ON
    # Disable install step
    INSTALL_COMMAND ""
    # Wrap download, configure and build steps in a script to log output
    LOG_DOWNLOAD ON
    LOG_CONFIGURE ON
    LOG_BUILD ON)

# Specify include dir
ExternalProject_Get_Property(googletest source_dir)
include_directories(${source_dir}/include)

# Add compiler flag for MSVC 2012
if(MSVC_VERSION EQUAL 1700)
  add_definitions(-D_VARIADIC_MAX=10)
endif()

# Add test executable target
add_executable(MainTest ${PROJECT_SOURCE_DIR}/src/main.cpp)

# Create dependency of MainTest on googletest
add_dependencies(MainTest googletest)

# Specify MainTest's link libraries
ExternalProject_Get_Property(googletest binary_dir)
if(MSVC)
  set(Suffix ".lib")
else()
  set(Suffix ".a")
  set(Pthread "-pthread")
endif()
target_link_libraries(
    MainTest
    debug ${binary_dir}/DebugLibs/${CMAKE_FIND_LIBRARY_PREFIXES}gtest${Suffix}
    optimized ${binary_dir}/ReleaseLibs/${CMAKE_FIND_LIBRARY_PREFIXES}gtest${Suffix}
    ${Pthread})

If you create this as CMakeLists.txt in an empty directory (say MyTest), then:

cd MyTest
mkdir build
cd build
cmake ..

This should create a basic main.cpp in MyTest/src and create a project file (MyTest/build/Test.sln on Windows)

When you build the project, it should download the gtest sources to MyTest/build/ThirdParty/src/googletest, and build them in MyTest/build/ThirdParty/src/googletest-build. You should then be able to run the MainTest target successfully.


It is long past when the original question being asked, but for the benefit of others, it is possible to use ExternalProject to download the gtest source and then use add_subdirectory() to add it to your build. This has the following advantages:

  • gtest is built as part of your main build, so it uses the same compiler flags, etc. and doesn't need to be installed anywhere.
  • There's no need to add the gtest sources to your own source tree.

Used in the normal way, ExternalProject won't do the download and unpacking at configure time (i.e. when CMake is run), but you can get it to do so. I've written a blog post on how to do this which also includes a generalised implementation which works for any external project which uses CMake as its build system, not just gtest. You can find it here:

https://crascit.com/2015/07/25/cmake-gtest/

Update: The approach described above is now also part of the googletest documentation.

Tags:

Googletest

Cmake

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