@Test
public void testPlusMonths()
{

    DateTimeUnit dateTimeUnit = new DateTimeUnit( 1382, 1, 20 );
    DateTimeUnit testDateTimeUnit = calendar.plusMonths( dateTimeUnit, 4 );
    assertEquals( 1382, testDateTimeUnit.getYear() );
    assertEquals( 5, testDateTimeUnit.getMonth() );
    assertEquals( 20, testDateTimeUnit.getDay() );
    dateTimeUnit = new DateTimeUnit( 1382, 1, 20 );
    testDateTimeUnit = calendar.plusMonths( dateTimeUnit, -4 );
    assertEquals( 1381, testDateTimeUnit.getYear() );
    assertEquals( 9, testDateTimeUnit.getMonth() );
    assertEquals( 20, testDateTimeUnit.getDay() );
}