def test_pop_raises(self):
a = Tracker(states)
with self.assertRaises(KeyError):
a.pop_state('foo', sentinel_a)
def test_pop_removes_from_all(self):
a = Tracker(states)
a.set_state('foo', sentinel_a)
a.set_state('foo', sentinel_b)
a.pop_state('foo', sentinel_a)
self.assertEqual({sentinel_b}, set(a.all))
def test_set_pop_value(self):
data = object()
a = Tracker(states)
a.set_state('foo', sentinel_a, data)
v = a.pop_state('foo', sentinel_a)
self.assertIs(data, v)