public void testPropertySetWeekOfWeekyear() {
        DateTime test = new DateTime(2004, 6, 7, 0, 0, 0, 0);
        DateTime copy = test.weekOfWeekyear().setCopy(4);
        assertEquals("2004-06-07T00:00:00.000+01:00", test.toString());
        assertEquals("2004-01-19T00:00:00.000Z", copy.toString());
        
        try {
            test.weekOfWeekyear().setCopy(54);
            fail();
        } catch (IllegalArgumentException ex) {}
        try {
            test.weekOfWeekyear().setCopy(0);
            fail();
        } catch (IllegalArgumentException ex) {}
    }