def test_unicodeChildSearchPreauth(self):
        """
        C{childSearchPreauth} called with L{unicode} on a L{unicode}-mode
        L{FilePath} will return a L{unicode}-mode L{FilePath}.
        """
        fp = filepath.FilePath(u"./mon\u20acy")
        fp.createDirectory()
        self.addCleanup(lambda: fp.remove())
        child = fp.child("text.txt")
        child.touch()

        newPath = fp.childSearchPreauth(u"text.txt")

        self.assertIsInstance(newPath, filepath.FilePath)
        self.assertIsInstance(newPath.path, unicode)

        C{childSearchPreauth} called with L{unicode} on a L{unicode}-mode
        L{FilePath} will return a L{unicode}-mode L{FilePath}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_paths.py