def METHOD_NAME(self):
    """Create a temporary directory with some file structure."""
    root_dir = tempfile.mkdtemp(prefix="mock_root")
    os.mkdir(osp.join(root_dir, "src"))
    with open(osp.join(root_dir, "src", "temp.txt"), "w") as fid:
        fid.write("hello")
    readonly_filepath = osp.join(root_dir, "src", "readonly-temp.txt")
    with open(readonly_filepath, "w") as fid:
        fid.write("hello from a readonly file")
    os.chmod(readonly_filepath, S_IRUSR | S_IRGRP | S_IROTH)
    atexit.register(lambda: shutil.rmtree(root_dir, True))
    return root_dir