public void testFactory_monthsBetween_RPartial_YearMonth() {
        YearMonth start1 = new YearMonth(2011, 1);
        for (int i = 0; i < 6; i++) {
            YearMonth start2 = new YearMonth(2011 + i, 1);
            YearMonth end = new YearMonth(2011 + i, 3);
            assertEquals(i * 12 + 2, Months.monthsBetween(start1, end).getMonths());
            assertEquals(2, Months.monthsBetween(start2, end).getMonths());
        }
    }