    @Test
    public void testPermutate() {

        Set<String> set = PermutationUtil.permutateSQL("-", "1");
        Assert.assertEquals(1, set.size());
        Assert.assertTrue(set.contains("1"));

        set = PermutationUtil.permutateSQL("-", "1", "1");
        Assert.assertEquals(1, set.size());
        Assert.assertTrue(set.contains("1-1"));

        set = PermutationUtil.permutateSQL("-", "1", "2");
        Assert.assertEquals(2, set.size());
        Assert.assertTrue(set.contains("1-2"));
        Assert.assertTrue(set.contains("2-1"));

        set = PermutationUtil.permutateSQL("-", "1", "2", "2");
        Assert.assertEquals(3, set.size());
        Assert.assertTrue(set.contains("1-2-2"));
        Assert.assertTrue(set.contains("2-1-2"));
        Assert.assertTrue(set.contains("2-2-1"));

        set = PermutationUtil.permutateSQL("-", "1", "2", "3");
        Assert.assertEquals(6, set.size());
        Assert.assertTrue(set.contains("1-2-3"));
        Assert.assertTrue(set.contains("1-3-2"));
        Assert.assertTrue(set.contains("2-1-3"));
        Assert.assertTrue(set.contains("2-3-1"));
        Assert.assertTrue(set.contains("3-2-1"));
        Assert.assertTrue(set.contains("3-1-2"));
    }