public void testPropertySetDayOfMonth() {
        DateTime test = new DateTime(2004, 6, 9, 0, 0, 0, 0);
        DateTime copy = test.dayOfMonth().setCopy(12);
        assertEquals("2004-06-09T00:00:00.000+01:00", test.toString());
        assertEquals("2004-06-12T00:00:00.000+01:00", copy.toString());
        
        try {
            test.dayOfMonth().setCopy(31);
            fail();
        } catch (IllegalArgumentException ex) {}
        try {
            test.dayOfMonth().setCopy(0);
            fail();
        } catch (IllegalArgumentException ex) {}
    }