@Test
    public void sizeIsCorrect()
    {
        boolean test = true;
        for (int i = 0; i < 1000; i++)
        {
            tree.clear();
            Random rand = new Random();
            int r = rand.nextInt(1000);
            for (int j = 0; j < r; j++) tree.add(j);
            int b = (r <= 0) ? 0 : rand.nextInt(r);
            for (int j = 0; j < b; j++) tree.remove(j);
            if (tree.size() != r - b)
            {
                test = false;
                break;
            }
        }
        assertTrue(test);
    }