'``datasets_from_deployment`` does not return datasets if there are only
replica manifestations.'

def test_replica_manifestations_only(self):

    manifestation1 = Manifestation(dataset=Dataset(dataset_id=unicode(uuid4())), primary=False)
    manifestation2 = Manifestation(dataset=Dataset(dataset_id=unicode(uuid4())), primary=False)
    node1 = Node(uuid=uuid4(), applications={}, manifestations={manifestation1.dataset_id: manifestation1})
    node2 = Node(uuid=uuid4(), applications={}, manifestations={manifestation2.dataset_id: manifestation2})
    deployment = Deployment(nodes=frozenset([node1, node2]))
    self.assertEqual([], list(datasets_from_deployment(deployment)))
