@Test
public void testCompareTo() {

    assertTrue(D_2001_01_03.compareTo(D_2001_01_03) == 0);
    assertTrue(D_2001_03_03.compareTo(D_2001_01_03) > 0);
    assertTrue(D_2001_01_03.compareTo(D_2001_03_03) < 0);
}