public function testUpdateCoupon()
{
$coupon1 = $this->dummyData->getCoupon();
$coupon2 = $this->dummyData->getCoupon();
$cart = new Cart();
$cart->addCoupon($coupon1);
$this->assertEntitiesEqual($coupon1, $cart->getCoupons()[0]);
$cart->updateCoupon(0, $coupon2);
$this->assertEntitiesEqual($coupon2, $cart->getCoupons()[0]);
}