def test_remove_black_cell(self):
grid = Grid(9)
grid.add_black_cell(1, 5)
grid.add_black_cell(4, 9)
grid.remove_black_cell(6, 1)
expected = [(1, 5), (9, 5)]
actual = grid.get_black_cells()
self.assertEqual(expected, actual)
def test_add__remove_black_cell(self):
grid = Grid(5)
grid.add_black_cell(1, 2)
self.assertEqual(True, grid.is_black_cell(1, 2))
self.assertEqual(True, grid.is_black_cell(5, 4))
self.assertEqual([(1, 2)], grid.undo_stack)
self.assertEqual([], grid.redo_stack)
grid.remove_black_cell(1, 2)
self.assertEqual(False, grid.is_black_cell(1, 2))
self.assertEqual(False, grid.is_black_cell(5, 4))
self.assertEqual([(1, 2), (1, 2)], grid.undo_stack)
self.assertEqual([], grid.redo_stack)
