Feature Request: test-specific source directory

[hagertnl]

It would be useful to have a test be able to supply additional files to be copied to the build_directory at the beginning of the build. For example, an alternative Makefile or a specific source file that is only needed for a specific test. For example:

app_1
|- Source
    |- Makefile
    |- hello_cpu.c
|- hello_gpu
    |- Source
        |- Makefile # a GPU-enabled Makefile
        |- hello_gpu.c
   |- Scripts
...

[hagertnl]

So I want to do something like:

shutil.copytree(src='Source',
                dst='build',
                symlinks=True)

shutil.copytree(src='test/Source',
                dst='build',
                symlinks=True, dirs_exist_ok=True)

But unfortunately, the dirs_exist_ok keyword was not until Python 3.8, and Frontier's default Python is 3.6. Given we have numerous machines that don't yet have Python 3.8 as default, this doesn't feel like a viable solution. Prior to Python 3.8, shutil.copytree does not support overwriting a directory that already exists. The dst directory must not exist.

[hagertnl]

After talking with Asa, I think the best solution is to have an if conditional -- if Python version > 3.8 is found, then use this dirs_exist_ok keyword. Otherwise, spawn a subprocess and use the Unix cp.