'``P2PManifestationDeployer.calculate_changes`` specifies no work for
the volume if it was and is supposed to be available on the node.'

def test_no_volume_changes(self):

    current_node = NodeState(hostname=u'node1.example.com', applications=frozenset({APPLICATION_WITH_VOLUME}), manifestations={MANIFESTATION.dataset_id: MANIFESTATION}, devices={}, paths={})
    desired_node = Node(hostname=u'node1.example.com', applications=frozenset({APPLICATION_WITH_VOLUME}), manifestations={MANIFESTATION.dataset_id: MANIFESTATION})
    current = DeploymentState(nodes=[current_node])
    desired = Deployment(nodes=[desired_node])
    api = P2PManifestationDeployer(current_node.hostname, create_volume_service(self))
    changes = api.calculate_changes(desired, current, NodeLocalState(node_state=current_node))
    expected = NO_CHANGES
    self.assertEqual(expected, changes)
