def test_getTimezoneOffsetWithoutDaylightSavingTime(self):
        """
        Attempt to verify that L{FileLogObserver.getTimezoneOffset} returns
        correct values for the current C{TZ} environment setting for at least
        some cases.  This test method exercises a timezone that does not use
        daylight saving time at all (so both summer and winter time test values
        should have the same offset).
        """
        # Test a timezone that doesn't have DST.  mktime() implementations
        # available for testing seem happy to produce results for this even
        # though it's not entirely valid.
        self._getTimezoneOffsetTest("Africa/Johannesburg", -7200, -7200)

        Attempt to verify that L{FileLogObserver.getTimezoneOffset} returns
        correct values for the current C{TZ} environment setting for at least
        some cases.  This test method exercises a timezone that does not use
        daylight saving time at all (so both summer and winter time test values
        should have the same offset).
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_log.py