def test_fetch_soonest_event(): tracker = Tracker() tracker.add_event('Buy snacks', 700) tracker.add_event('Go shopping', 1200) tracker.add_event('Eat something', 900) assert tracker.fetch_soonest_event() == 'Buy snacks' tracker.delete_event('Buy snacks') assert tracker.fetch_soonest_event() == 'Eat something' tracker.delete_event('Go shopping') tracker.delete_event('Eat something') assert tracker.fetch_soonest_event() == None