public function testDeleteQty()
{
$product = new Product();
$product->setQty(6);
$item = new Item();
$item->setQty(4);
$item->setProduct($product);
PurchaseItemManager::deleteQty($item);
$this->assertEquals(2, $item->getProduct()->getQty(), "Unexpected value for qty in product for deleteQty method ");
}