/**
* Check if cart meets basic requirements for a coupon
*
* @param CartInterface $cart Cart
* @param CouponInterface $coupon Coupon
*
* @throws CouponIncompatibleException Coupon incompatible
*/
public function validateCoupon(CartInterface $cart, CouponInterface $coupon)
{
if ($cart->getTotalItemNumber() === 0) {
throw new CouponIncompatibleException();
}
$this->couponManager->checkCoupon($coupon);
}