def test_defaultAuths(self):
        """
        Make sure that if the C{--auth} command-line option is not passed,
        the default checkers are (for backwards compatibility): SSH and UNIX
        """
        numCheckers = 2

        self.assertIn(ISSHPrivateKey, self.options['credInterfaces'],
            "SSH should be one of the default checkers")
        self.assertIn(IUsernamePassword, self.options['credInterfaces'],
            "UNIX should be one of the default checkers")
        self.assertEqual(numCheckers, len(self.options['credCheckers']),
            "There should be %d checkers by default" % (numCheckers,))

        Make sure that if the C{--auth} command-line option is not passed,
        the default checkers are (for backwards compatibility): SSH and UNIX
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_tap.py