public void testPropertySetDayOfMonth() {
        MonthDay test = new MonthDay(4, 6);
        MonthDay copy = test.dayOfMonth().setCopy(12);
        check(test, 4, 6);
        check(copy, 4, 12);
        
        try {
            test.dayOfMonth().setCopy(33);
            fail();
        } catch (IllegalArgumentException ex) {}
        try {
            test.dayOfMonth().setCopy(0);
            fail();
        } catch (IllegalArgumentException ex) {}
    }