def test_returnsFileLogObserver(self):
        with StringIO() as fileHandle:
            observer = textFileLogObserver(fileHandle)
            self.assertIsInstance(observer, FileLogObserver)
L{textFileLogObserver} returns a L{FileLogObserver}.
dataset/ETHPy150Open twisted/twisted/twisted/logger/test/test_file.py/TextFileLogObserverTests.test_returnsFileLogObserver