When\When::byweekno PHP Method

    public function byweekno($bywknolist, $delimiter = ",")
    {
        if ($this->byweeknos = self::prepareItemsList($bywknolist, $delimiter, 'weekNum')) {
            return $this;
        }
        throw new \InvalidArgumentException("byweekno: Accepts positive and negative values between 1 and 53");
    }

 /**
  * @expectedException InvalidArgumentException
  */
 public function testInvalidByWeekNo()
 {
     $test = new When();
     $test->byweekno(55);
 }