Prado\Collections\TStack::getIterator PHP Метод

    public function getIterator()
    {
        return new \ArrayIterator($this->_d);
    }

 public function testGetIterator()
 {
     $stack = new TStack(array(1, 2));
     self::assertInstanceOf('ArrayIterator', $stack->getIterator());
     $n = 0;
     $found = 0;
     foreach ($stack as $index => $item) {
         foreach ($stack as $a => $b) {
         }
         // test of iterator
         $n++;
         if ($index === 0 && $item === 1) {
             $found++;
         }
         if ($index === 1 && $item === 2) {
             $found++;
         }
     }
     self::assertTrue($n == 2 && $found == 2);
 }