def test_listLogsIgnoresZeroSuffixedFiles(self):
        """
        L{LogFile.listLogs} ignores log files which rotated suffix is 0.
        """
        log = logfile.LogFile(self.name, self.dir)
        self.addCleanup(log.close)

        for i in range(0, 3):
            with open("{0}.{1}".format(log.path, i), "w") as fp:
                fp.write("123")

        self.assertEqual([1, 2], log.listLogs())

        L{LogFile.listLogs} ignores log files which rotated suffix is 0.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_logfile.py