'If the challenge just has a rspauth directive, the response is empty.'

def test_getResponseRspauth(self):

    challenge = 'rspauth=cnNwYXV0aD1lYTQwZjYwMzM1YzQyN2I1NTI3Yjg0ZGJhYmNkZmZmZA=='
    response = self.mechanism.getResponse(challenge)
    self.assertEqual('', response)
