@Test
public void testNumberOfDays() throws Exception {

    OpeningHoursInterval interval = new OpeningHoursInterval(5, 6, "9 - 10");// saturday - sunday
    assertEquals(2,interval.getNumberOfDays());
    interval = new OpeningHoursInterval(0, 6, "9 - 10");// monday - sunday
    assertEquals(7,interval.getNumberOfDays());
    interval = new OpeningHoursInterval(0, "9 - 10");// monday
    assertEquals(1,interval.getNumberOfDays());
}