if(NOT PROJECT_BUILD AND PROJECT_ENABLE_TESTING)
  add_definitions(-DPROJECT_ENABLE_TESTING)

  if(NOT PROJECT_IS_MINGW OR CMAKE_HOST_WIN32)
    ExternalProject_Add(gtest_project
      PREFIX external
      URL ${PROJECT_3RD_PARTY_DIR}/googletest-${GTEST_VERSION}.tar.gz
      URL_HASH SHA256=7315acb6bf10e99f332c8a43f00d5fbb1ee6ca48c52f6b936991b216c586aaad
      LIST_SEPARATOR |
      CMAKE_ARGS ${PROJECT_EXTERNAL_CMAKE_FLAGS}
        -DBUILD_SHARED_LIBS=${PROJECT_BUILD_SHARED_LIBS}
        -DBUILD_STATIC_LIBS=ON
    )

    set(PROJECT_DEPENDENCIES 
      ${PROJECT_DEPENDENCIES}
      gtest_project
    )
  endif()
endif()