Neos\Flow\Http\Response::getAge PHP Method

    public function getAge()
    {
        if ($this->headers->has('Age')) {
            return $this->headers->get('Age');
        } else {
            $dateTimestamp = $this->headers->get('Date')->getTimestamp();
            $nowTimestamp = $this->now->getTimestamp();
            return $nowTimestamp > $dateTimestamp ? $nowTimestamp - $dateTimestamp : 0;
        }
    }

 /**
  * @test
  */
 public function getAgeReturnsTimeSpecifiedInAgeHeaderIfExists()
 {
     $now = \DateTime::createFromFormat(DATE_RFC2822, 'Tue, 22 May 2012 12:00:00 GMT');
     $response = new Response();
     $response->setNow($now);
     $response->setHeader('Age', 123);
     $this->assertSame(123, $response->getAge());
 }