def test_get_rover_on_position(self): planet = Planet(5, 5) rover = Rover(2, 1, 'N', planet) planet.add_rover(rover) planet.update_grid() self.assertIsInstance(planet.get_rover_on_position(2, 1), Rover) self.assertEqual(planet.get_rover_on_position(2, 1), rover) rover2 = Rover(3, 5, 'S', planet) planet.add_rover(rover2) planet.update_grid() self.assertEqual(planet.get_rover_on_position(3, 5), rover2)