public void testForFields_datetime_YH() {
        DateTimeFieldType[] fields = new DateTimeFieldType[] {
                DateTimeFieldType.year(),
                DateTimeFieldType.hourOfDay(),
        };
        int[] values = new int[] {2005, 12};
        List types = new ArrayList(Arrays.asList(fields));
        DateTimeFormatter f = ISODateTimeFormat.forFields(types, true, false);
        assertEquals("2005T12", f.print(new Partial(fields, values)));
        assertEquals(0, types.size());
        
        types = new ArrayList(Arrays.asList(fields));
        f = ISODateTimeFormat.forFields(types, false, false);
        assertEquals("2005T12", f.print(new Partial(fields, values)));
        assertEquals(0, types.size());
        
        types = new ArrayList(Arrays.asList(fields));
        try {
            ISODateTimeFormat.forFields(types, true, true);
            fail();
        } catch (IllegalArgumentException ex) {}
        
        types = new ArrayList(Arrays.asList(fields));
        try {
            ISODateTimeFormat.forFields(types, false, true);
            fail();
        } catch (IllegalArgumentException ex) {}
    }