def test_removeObserver(self):
observable = Observable()
self.assertFalse(observable.removeObserver(None))
self.assertFalse(observable.removeObserver("wrong"))
self.assertFalse(observable.removeObserver(Observable()))
obs1 = Observer()
observable.addObserver(obs1)
obs2 = Observer()
observable.addObserver(obs2)
self.assertTrue(observable.removeObserver(obs1))
self.assertFalse(observable.removeObserver(obs1))
self.assertTrue(observable.removeObserver(obs2))
