public void test_compareTo() {
        assertEquals(0, iField.compareTo(iField));
        assertEquals(-1, iField.compareTo(ISOChronology.getInstance().minutes()));
        DurationField dummy = new PreciseDurationField(DurationFieldType.minutes(), 0);
        assertEquals(1, iField.compareTo(dummy));
//        try {
//            iField.compareTo("");
//            fail();
//        } catch (ClassCastException ex) {}
        try {
            iField.compareTo(null);
            fail();
        } catch (NullPointerException ex) {}
    }