public void testWithers() {
        TimeOfDay test = new TimeOfDay(10, 20, 30, 40);
        check(test.withHourOfDay(6), 6, 20, 30, 40);
        check(test.withMinuteOfHour(6), 10, 6, 30, 40);
        check(test.withSecondOfMinute(6), 10, 20, 6, 40);
        check(test.withMillisOfSecond(6), 10, 20, 30, 6);
        try {
            test.withHourOfDay(-1);
            fail();
        } catch (IllegalArgumentException ex) {}
        try {
            test.withHourOfDay(24);
            fail();
        } catch (IllegalArgumentException ex) {}
    }