@Test
public void testTimeDifferenceInSeconds() {

    ISODate date1 = new ISODate("1976-6-3T1:2:3");
    ISODate date2 = new ISODate("1976-6-3T1:2:30");
    assertEquals(27, date2.timeDifferenceInSeconds(date1));
    assertEquals(-27, date1.timeDifferenceInSeconds(date2));
}