'``enumerate()`` returns all volumes previously ``create()``ed.'

def test_enumerate_some_volumes(self):

    pool = FilesystemStoragePool(FilePath(self.mktemp()))
    service = VolumeService(FilePath(self.mktemp()), pool, reactor=Clock())
    service.startService()
    names = set((VolumeName(namespace=u'ns', dataset_id=i) for i in (u'somevolume', u'anotherone', u'lastone')))
    expected = {self.successResultOf(service.create(service.get(name))) for name in names}
    service2 = VolumeService(FilePath(self.mktemp()), pool, reactor=Clock())
    service2.startService()
    actual = self.successResultOf(service2.enumerate())
    self.assertEqual(set(((volume.node_id, volume.name) for volume in expected)), set(((volume.node_id, volume.name) for volume in actual)))
