MC-37884: [GraphQL] Cart Price Rule for the Whole Cart with coupon does not apply

Author: serhii-balko

app/code/Magento/QuoteGraphQl/Model/Resolver/CartPrices.php

@@ -14,6 +14,7 @@
 use Magento\Quote\Model\Quote;
 use Magento\Quote\Model\Quote\Address\Total;
 use Magento\Quote\Model\Quote\TotalsCollector;
+use Magento\SalesRule\Model\Spi\QuoteResetAppliedRulesInterface;
 
 /**
  * @inheritdoc
@@ -25,13 +26,21 @@ class CartPrices implements ResolverInterface
      */
     private $totalsCollector;
 
+    /**
+     * @var QuoteResetAppliedRulesInterface
+     */
+    private $resetAppliedRules;
+
     /**
      * @param TotalsCollector $totalsCollector
+     * @param QuoteResetAppliedRulesInterface $resetAppliedRules
      */
     public function __construct(
-        TotalsCollector $totalsCollector
+        TotalsCollector $totalsCollector,
+        QuoteResetAppliedRulesInterface $resetAppliedRules
     ) {
         $this->totalsCollector = $totalsCollector;
+        $this->resetAppliedRules = $resetAppliedRules;
     }
 
     /**
@@ -45,6 +54,12 @@ public function resolve(Field $field, $context, ResolveInfo $info, array $value
 
         /** @var Quote $quote */
         $quote = $value['model'];
+        /**
+         * To calculate a right discount value
+         * before calculate totals
+         * need to reset Cart Fixed Rules in the quote
+         */
+        $this->resetAppliedRules->execute($quote);
         $cartTotals = $this->totalsCollector->collectQuoteTotals($quote);
         $currency = $quote->getQuoteCurrencyCode();
 

dev/tests/api-functional/testsuite/Magento/GraphQl/Quote/Guest/ApplyCouponsToCartTest.php

@@ -21,6 +21,9 @@ class ApplyCouponsToCartTest extends GraphQlAbstract
      */
     private $getMaskedQuoteIdByReservedOrderId;
 
+    /**
+     * @inheritdoc
+     */
     protected function setUp(): void
     {
         $objectManager = Bootstrap::getObjectManager();
@@ -36,12 +39,17 @@ protected function setUp(): void
     public function testApplyCouponsToCart()
     {
         $couponCode = '2?ds5!2d';
+        $expectedGrandTotal = 15.00;
         $maskedQuoteId = $this->getMaskedQuoteIdByReservedOrderId->execute('test_quote');
         $query = $this->getQuery($maskedQuoteId, $couponCode);
         $response = $this->graphQlMutation($query);
 
         self::assertArrayHasKey('applyCouponToCart', $response);
         self::assertEquals($couponCode, $response['applyCouponToCart']['cart']['applied_coupons'][0]['code']);
+        self::assertEquals(
+            $expectedGrandTotal,
+            $response['applyCouponToCart']['cart']['prices']['grand_total']['value']
+        );
     }
 
     /**
@@ -146,6 +154,11 @@ private function getQuery(string $maskedQuoteId, string $couponCode): string
       applied_coupons {
         code
       }
+      prices {
+        grand_total {
+          value
+        }
+      }
     }
   }
 }