def test_formatTimeWithNoTime(self):
        """
        If C{when} argument is L{None}, we get the default output.
        """
        self.assertEqual(formatTime(None), u"-")
        self.assertEqual(formatTime(None, default=u"!"), u"!")

        If C{when} argument is L{None}, we get the default output.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/logger/test/test_format.py