Add tests and implementation

features/promotion/applying_promotion_coupon/denying_usage_of_unexisting_promotion_coupon.feature

@@ -10,7 +10,7 @@ Feature: Denying usage of unexisting promotion coupon
         And the store has promotion "Christmas sale" with coupon "SANTA2016"
         And this promotion gives "$10.00" discount to every order
 
-    @ui
+    @ui @api
     Scenario: Receiving no discount from unexisting coupon
         When I add product "PHP T-Shirt" to the cart
         And I use coupon with code "SANTA2011"

src/Sylius/Bundle/ApiBundle/Validator/Constraints/PromotionCouponEligibilityValidator.php

@@ -59,14 +59,23 @@ public function validate($value, Constraint $constraint): void
             return;
         }
 
-        /** @var PromotionCouponInterface $promotionCoupon */
+        /** @var PromotionCouponInterface|null $promotionCoupon */
         $promotionCoupon = $this->promotionCouponRepository->findOneBy(['code' => $value->couponCode]);
 
         /** @var OrderInterface $cart */
         $cart = $this->orderRepository->findCartByTokenValue($value->getOrderTokenValue());
 
         $cart->setPromotionCoupon($promotionCoupon);
 
+        if ($promotionCoupon === null) {
+            $this->context->buildViolation('sylius.promotion_coupon.not_exist')
+                ->atPath('couponCode')
+                ->addViolation()
+            ;
+
+            return;
+        }
+
         if (!$this->promotionCouponChecker->isEligible($cart, $promotionCoupon)) {
             $this->context->buildViolation('sylius.promotion_coupon.is_invalid')
                 ->atPath('couponCode')

src/Sylius/Bundle/ApiBundle/spec/Validator/Constraints/PromotionCouponEligibilityValidatorSpec.php

@@ -157,4 +157,30 @@ function it_does_add_violation_if_promotion_is_not_eligible(
 
         $this->validate($value, $constraint);
     }
+
+    function it_does_add_violation_if_promotion_code_does_not_exist(
+        PromotionCouponRepositoryInterface $promotionCouponRepository,
+        OrderRepositoryInterface $orderRepository,
+        OrderInterface $cart,
+        ExecutionContextInterface $executionContext,
+        ConstraintViolationBuilderInterface $constraintViolationBuilder
+    ): void {
+        $this->initialize($executionContext);
+        $constraint = new PromotionCouponEligibility();
+
+        $value = new ApplyCouponToCart('couponCode');
+        $value->setOrderTokenValue('token');
+
+        $promotionCouponRepository->findOneBy(['code' => 'couponCode'])->willReturn(null);
+
+        $orderRepository->findCartByTokenValue('token')->willReturn($cart);
+
+        $cart->setPromotionCoupon(null)->shouldBeCalled();
+
+        $executionContext->buildViolation('sylius.promotion_coupon.not_exist')->willReturn($constraintViolationBuilder);
+        $constraintViolationBuilder->atPath('couponCode')->willReturn($constraintViolationBuilder);
+        $constraintViolationBuilder->addViolation()->shouldBeCalled();
+
+        $this->validate($value, $constraint);
+    }
 }

src/Sylius/Bundle/PromotionBundle/Resources/translations/validators.en.yml

@@ -28,6 +28,7 @@ sylius:
             regex: Coupon code can only be comprised of letters, numbers, dashes and underscores.
             unique: This coupon already exists.
         is_invalid: Coupon code is invalid.
+        not_exist: Coupon code not exist.
         usage_limit:
             min: Coupon usage limit must be at least {{ limit }}.
     promotion_coupon_generator_instruction: