def test_failOnKeyError(self):
        def getpwnam(username):
            raise KeyError(username)
        checker = checkers.UNIXPasswordDatabase([getpwnam])
        credential = UsernamePassword('username', 'username')
        self.assertUnauthorizedLogin(checker.requestAvatarId(credential))
If the getpwnam function raises a KeyError, the login fails with an
dataset/ETHPy150Open nlloyd/SubliminalCollaborator/libs/twisted/conch/test/test_checkers.py/UNIXPasswordDatabaseTests.test_failOnKeyError