def test_failOnSpecial(self):
        """
        If the password returned by any function is C{""}, C{"x"}, or C{"*"} it
        is not compared against the supplied password.  Instead it is skipped.
        """
        pwd = UserDatabase()
        pwd.addUser('alice', '', 1, 2, '', 'foo', 'bar')
        pwd.addUser('bob', 'x', 1, 2, '', 'foo', 'bar')
        pwd.addUser('carol', '*', 1, 2, '', 'foo', 'bar')
        self.patch(checkers, 'pwd', pwd)

        checker = checkers.UNIXPasswordDatabase([checkers._pwdGetByName])
        cred = UsernamePassword(b'alice', b'')
        self.assertUnauthorizedLogin(checker.requestAvatarId(cred))

        cred = UsernamePassword(b'bob', b'x')
        self.assertUnauthorizedLogin(checker.requestAvatarId(cred))

        cred = UsernamePassword(b'carol', b'*')
        self.assertUnauthorizedLogin(checker.requestAvatarId(cred))

        If the password returned by any function is C{""}, C{"x"}, or C{"*"} it
        is not compared against the supplied password.  Instead it is skipped.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_checkers.py