def testWithoutOldData(self):
   new = {
     constants.DT_PLAIN: {
       "xenvg": {
         constants.DS_DISK_RESERVED: 1024,
         },
       },
     }
   self.assertEqual(common.MergeAndVerifyDiskState(new, None), new)
 def testWithoutOpData(self):
   self.assertEqual(common.MergeAndVerifyDiskState(None, NotImplemented),
                    None)