Add api test for coupon_unique_code_validation.feature

features/promotion/managing_coupons/coupon_unique_code_validation.feature

@@ -9,7 +9,7 @@ Feature: Coupon unique code validation
         And the store has promotion "Christmas sale" with coupon "SANTA2016"
         And I am logged in as an administrator
 
-    @ui
+    @api @ui
     Scenario: Trying to add coupon with taken code
         When I want to create a new coupon for this promotion
         And I specify its code as "SANTA2016"

features/promotion/managing_coupons/editing_coupon.feature

@@ -41,7 +41,7 @@ Feature: Editing promotion coupon
         Then I should be notified that it has been successfully edited
         And this coupon should not be reusable from cancelled orders
 
-    @ui @no-api
-    Scenario: Seeing a disabled code field when editing a coupon
+    @ui @api
+    Scenario: Being unable to change code of promotion coupon
         When I want to modify the "SANTA2016" coupon for this promotion
-        Then the code field should be disabled
+        Then I should not be able to edit its code

src/Sylius/Behat/Context/Api/Admin/ManagingPromotionCouponsContext.php

@@ -335,6 +335,17 @@ public function couponShouldStillExistInTheRegistry(PromotionCouponInterface $co
         ));
     }
 
+    /**
+     * @Then /^there should still be only one coupon with code "([^"]+)" related to (this promotion)$/
+     */
+    public function thereShouldStillBeOnlyOneCouponWithCodeRelatedTo(string $code, PromotionInterface $promotion): void
+    {
+        Assert::count(
+            $this->responseChecker->getCollectionItemsWithValue($this->client->index(Resources::PROMOTION_COUPONS), 'code', $code),
+            1
+        );
+    }
+
     /**
      * @Then I should be notified that it is in use and cannot be deleted
      */
@@ -423,6 +434,32 @@ public function iShouldBeNotifiedThatOnlyCouponBasedPromotionsCanHaveCoupons():
         );
     }
 
+    /**
+     * @Then I should be notified that coupon with this code already exists
+     */
+    public function iShouldBeNotifiedThatCouponWithThisCodeAlreadyExists(): void
+    {
+        $response = $this->client->getLastResponse();
+        Assert::false(
+            $this->responseChecker->isCreationSuccessful($response),
+            'Coupon has been created successfully, but it should not',
+        );
+        Assert::same(
+            $this->responseChecker->getError($response),
+            'code: This coupon already exists.',
+        );
+    }
+
+    /**
+     * @Then I should not be able to edit its code
+     */
+    public function iShouldNotBeAbleToEditItsCode(): void
+    {
+        $this->client->updateRequestData(['code' => 'NEW_CODE']);
+
+        Assert::false($this->responseChecker->hasValue($this->client->update(), 'code', 'NEW_CODE'));
+    }
+
     private function sortBy(string $order, string $field): void
     {
         $this->client->sort([$field => str_starts_with($order, 'de') ? 'desc' : 'asc']);

src/Sylius/Behat/Context/Ui/Admin/ManagingPromotionCouponsContext.php

@@ -371,9 +371,10 @@ public function thisCouponShouldBeReusableFromCancelledOrders(PromotionCouponInt
     }
 
     /**
+     * @Then I should not be able to edit its code
      * @Then the code field should be disabled
      */
-    public function theCodeFieldShouldBeDisabled()
+    public function iShouldNotBeAbleToEditItsCode(): void
     {
         Assert::true($this->updatePage->isCodeDisabled());
     }