'``Configuration.model_from_configuration`` returns an empty
``Deployment`` object if supplied with empty configurations.'

def test_model_from_configuration_empty(self):

    application_configuration = {}
    deployment_configuration = {u'nodes': {}, u'version': 1}
    result = model_from_configuration(DeploymentState(), application_configuration, deployment_configuration)
    expected_result = Deployment(nodes=frozenset())
    self.assertEqual(expected_result, result)
