public void testToStandardDays_years() {
        Period test = Period.years(1);
        try {
            test.toStandardDays();
            fail();
        } catch (UnsupportedOperationException ex) {}
        
        test = Period.years(-1);
        try {
            test.toStandardDays();
            fail();
        } catch (UnsupportedOperationException ex) {}
        
        test = Period.years(0);
        assertEquals(0, test.toStandardDays().getDays());
    }