Newscoop\Package\Package::getNext PHP Метод

    public function getNext(Item $currentItem)
    {
        $iterator = $this->items->getIterator();
        foreach ($iterator as $item) {
            if ($item === $currentItem) {
                $iterator->next();
                return $iterator->valid() ? $iterator->current() : null;
            }
        }
    }

 public function testPrevNextItem()
 {
     $package = new Package();
     $first = new Item($package, new LocalImage('first'));
     $this->assertNull($package->getPrev($first));
     $this->assertNull($package->getNext($first));
     $second = new Item($package, new LocalImage('second'));
     $this->assertEquals($first, $package->getPrev($second));
     $this->assertEquals($second, $package->getNext($first));
 }