public void testFactory_parseMonths_String() {
        assertEquals(0, Months.parseMonths((String) null).getMonths());
        assertEquals(0, Months.parseMonths("P0M").getMonths());
        assertEquals(1, Months.parseMonths("P1M").getMonths());
        assertEquals(-3, Months.parseMonths("P-3M").getMonths());
        assertEquals(2, Months.parseMonths("P0Y2M").getMonths());
        assertEquals(2, Months.parseMonths("P2MT0H0M").getMonths());
        try {
            Months.parseMonths("P1Y1D");
            fail();
        } catch (IllegalArgumentException ex) {
            // expeceted
        }
        try {
            Months.parseMonths("P1MT1H");
            fail();
        } catch (IllegalArgumentException ex) {
            // expeceted
        }
    }