def use_dir(tmpdir_factory):
    """Create a sample data directory for testing.

    Directory layout::
    use_me
        |-- me_too
        |    +-- 03.py
        |-- 01.py
        |-- 02.py
        +-- 03.txt

    """
    use_me = tmpdir_factory.mktemp('use_me')
    files = [use_me.join(arg) for arg in ['01.py', '02.py', '03.txt']]
    files.append(use_me.join('me_too', '03.py'))

    for tmp_file in files:
        tmp_file.write('', ensure=True)
    return use_me