def METHOD_NAME(self, carbonlink_query):
    self.create_whisper_hosts()
    self.addCleanup(self.wipe_whisper_hosts)
    carbonlink_query.return_value = {}
    reader = WhisperReader(self.worker1, 'hosts.worker1.cpu')
    (_, values) = reader.fetch(self.start_ts-5, self.start_ts)
    self.assertEqual(values, [None, None, None, None, 1.0])