def test_filePathDeltaSubdir(self):
        self.assertEqual(filePathDelta(FilePath("/foo/bar"),
                                       FilePath("/foo/bar/baz")),
                         ["baz"])
L{filePathDelta} can create a simple relative path to a child path.
dataset/ETHPy150Open twisted/twisted/twisted/python/test/test_release.py/FilePathDeltaTests.test_filePathDeltaSubdir