    @Test
    public void testLengthNorm() {

        MySimilarity s = new MySimilarity();
        assertEquals(0, s.lengthNorm("test", 0), 1e-6);
        assertEquals(0.289400, s.lengthNorm("test", 10), 1e-6);
        assertEquals(0.234860, s.lengthNorm("test", 19), 1e-6);
        assertEquals(0.223606, s.lengthNorm("test", 20), 1e-6);
    }