def METHOD_NAME(self, tmp_path: Path) -> None:
    """Test version_file."""
    mod_path = tmp_path / "mod"
    overlay_path = mod_path / "overlay"
    overlay_path.mkdir(parents=True)
    obj = KBEnvManager(mod_path)
    # no version file
    assert not obj.version_file
    del obj.version_file
    # version file in parent dir
    expected = tmp_path / KB_VERSION_FILENAME
    expected.touch()
    assert obj.version_file == expected
    del obj.version_file
    # version file in module dir
    expected = mod_path / KB_VERSION_FILENAME
    expected.touch()
    assert obj.version_file == expected
    del obj.version_file
    # version file in overlay dir
    expected = overlay_path / KB_VERSION_FILENAME
    expected.touch()
    assert obj.version_file == mod_path / KB_VERSION_FILENAME
    assert (
        KBEnvManager(mod_path, overlay_path=overlay_path).version_file == expected
    )