public void testFactory_FromDateFields() throws Exception {
        GregorianCalendar cal = new GregorianCalendar(1970, 1, 3, 4, 5, 6);
        cal.set(Calendar.MILLISECOND, 7);
        MonthDay expected = new MonthDay(2, 3);
        assertEquals(expected, MonthDay.fromDateFields(cal.getTime()));
        try {
            MonthDay.fromDateFields(null);
            fail();
        } catch (IllegalArgumentException ex) {}
    }