The CMake helper 'create_test_executable' supports an option to sync a directory over to the build directory: 'ADDITIONAL_DIRECTORIES'.
When creating a test executable we may want to sync the contents of a directory (such as a set of configs). This being a path we want the test executable to be able to access when running in its binary location. This in particular is used by the CPP suite.
CMake currently won't detect and sync over new files added to the source directory. It only copies over the contents of a directory that are seen at the initial configuration time. We want CMake to sync over new files as they are added, whenever a subsequent configuration step is run. We possibly want to use the CMake feature: CONFIGURE_DEPENDS (https://cmake.org/cmake/help/latest/command/file.html#glob).