find_package(Git) # target to download test data add_custom_target(download_test_data COMMAND test -d json_test_data || ${GIT_EXECUTABLE} clone https://github.com/nlohmann/json_test_data.git --quiet --depth 1 COMMENT "Downloading test data from https://github.com/nlohmann/json_test_data" WORKING_DIRECTORY ${CMAKE_BINARY_DIR} ) # create a header with the path to the downloaded test data file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/include/test_data.hpp "#define TEST_DATA_DIRECTORY \"${CMAKE_BINARY_DIR}/json_test_data\"")