Sonata\Component\Basket\BasketElement::setQuantity PHP Method

    public function setQuantity($quantity)
    {
        $this->quantity = $quantity >= 0 ? $quantity : 1;
    }

 /**
  * Test quantity setter, if quantity is negative, must returns a quantity of 1
  */
 public function testNegativeQuantity()
 {
     $basketElement = new BasketElement();
     $basketElement->setQuantity(50);
     $this->assertEquals(50, $basketElement->getQuantity());
     $basketElement->setQuantity(-50);
     $this->assertEquals(1, $basketElement->getQuantity());
 }