def test_invalid_states(self):
state1 = Puzzle('12345')
with self.assertRaises(ValueError):
state1.generate_states()
state2 = Puzzle('123456789')
with self.assertRaises(ValueError):
state2.generate_states()
def test_generate_states(self):
state = Puzzle('12345678X')
possible_states = state.generate_states()
must_be = [Puzzle('12345X786'), Puzzle('1234567X8')]
self.assertCountEqual(possible_states, must_be)