def test_last_observation_when_no_observation_exists(self):
site = Website('https://example.com', 'example')
site.clean()
observation = site.last_observation()
self.assertEqual(observation, None)
def test_last_observation_happy_path(self):
site = Website('https://example.com', 'example')
site.new_observation('up')
last = site.last_observation()
self.assertEqual(last.status, 'up')