def test_merge_with_empty(self):
observer1 = LastValueAggregator()
observer2 = LastValueAggregator()
observer1.checkpoint = 23
observer1.last_update_timestamp = 100
observer1.merge(observer2)
self.assertEqual(observer1.checkpoint, 23)
self.assertEqual(observer1.last_update_timestamp, 100)
def test_merge_last_updated_none(self):
observer1 = LastValueAggregator()
observer2 = LastValueAggregator()
observer1.checkpoint = 23
observer2.checkpoint = 47
observer1.last_update_timestamp = 0
observer2.last_update_timestamp = 100
observer1.merge(observer2)
self.assertEqual(observer1.checkpoint, 47)
self.assertEqual(observer1.last_update_timestamp, 100)