@Test
    public void testCompareTo_normal_notMatch() {
        int[][] ints = {
                {1, 2, 3},
                {4, 6, 7},
                {8, 9, PuzzuleNode.EMPTY}
        };
        Node node = new PuzzuleNode(ints, 2, 2);

        int[][] ints2 = {
                {2, 3, 3},
                {4, 6, 7},
                {8, 9, PuzzuleNode.EMPTY}
        };

        Node node2 = new PuzzuleNode(ints2, 2, 2);

        assertFalse(node.equals(node2));
    }