public function testAddHolidays()
{
$holiday = new \DateTime('2015-05-11');
$holidayRange = new DateRange(new \DateTime('2015-07-08'), new \DateTime('2015-07-21'));
$holidays = new Holidays();
$holidays->addHolidays([$holiday]);
$holidays->addHolidays($holidayRange);
$this->assertTrue($holidays->isHoliday($holiday));
$this->assertTrue($holidays->isHoliday(new \DateTime('2015-07-09 10:00')));
}