def test_misplaced_tiles(self):
init_tile = np.array([[1, 2, 3], [0, 4, 6], [7, 5, 8]])
goal_tile = np.array([[1, 2, 3], [4, 5, 6], [7, 8, 0]])
init = State(init_tile, 0, 0)
goal = State(goal_tile, 0, 0)
self.assertEqual(init.misplaced_tiles(goal), 4)
