def test_swap_by_coordinates():
# Arrange
puzzle = Puzzle()
puzzle.position = np.array([[1, 2, 3, 4],
[5, 6, 7, 8],
[9, 10, 11, 12],
[13, 14, 15, 0]])
# Act
puzzle._Puzzle__swap_by_coordinates(0, 0, 1, 1)
# Assert
expected_swapped = np.array([[6, 2, 3, 4],
[5, 1, 7, 8],
[9, 10, 11, 12],
[13, 14, 15, 0]])
assert np.array_equal(puzzle.position, expected_swapped)
