LYNX-702: EstimateTotals: Discounts is null for virtual product types (#342)

Author: deepak-soni1

app/code/Magento/QuoteGraphQl/Model/GetDiscounts.php

@@ -22,6 +22,8 @@ class GetDiscounts
      */
     public function execute(Quote $quote, array $discounts): ?array
     {
+        $discounts = $discounts ?: $quote->getBillingAddress()->getExtensionAttributes()->getDiscounts() ?? [];
+
         if (empty($discounts)) {
             return null;
         }

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

@@ -0,0 +1,201 @@
+<?php
+/**
+ * Copyright 2025 Adobe
+ * All Rights Reserved.
+ */
+declare(strict_types=1);
+
+namespace Magento\GraphQl\Quote;
+
+use Exception;
+use Magento\Catalog\Test\Fixture\Product as ProductFixture;
+use Magento\Checkout\Test\Fixture\SetBillingAddress as SetBillingAddressFixture;
+use Magento\Customer\Test\Fixture\Customer as CustomerFixture;
+use Magento\Framework\Exception\AuthenticationException;
+use Magento\Framework\Exception\LocalizedException;
+use Magento\Integration\Api\CustomerTokenServiceInterface;
+use Magento\Quote\Test\Fixture\AddProductToCart as AddProductToCartFixture;
+use Magento\Quote\Test\Fixture\CustomerCart as CustomerCartFixture;
+use Magento\Quote\Test\Fixture\QuoteIdMask;
+use Magento\SalesRule\Model\Rule as SalesRule;
+use Magento\SalesRule\Test\Fixture\AddressCondition as AddressConditionFixture;
+use Magento\SalesRule\Test\Fixture\Rule as SalesRuleFixture;
+use Magento\Quote\Test\Fixture\ApplyCoupon as ApplyCouponFixture;
+use Magento\TestFramework\Fixture\DataFixture;
+use Magento\TestFramework\Fixture\DataFixtureStorage;
+use Magento\TestFramework\Fixture\DataFixtureStorageManager;
+use Magento\TestFramework\Helper\Bootstrap;
+use Magento\TestFramework\TestCase\GraphQlAbstract;
+
+/**
+ * Test getting estimateTotals schema with discounts fields for virtual products
+ */
+class EstimateTotalsWithVirtualProductDiscountsTest extends GraphQlAbstract
+{
+    private const PRODUCT_PRICE = 100;
+    private const DISCOUNT_PERCENTAGE = 20;
+    private const TOTAL_QTY = 1;
+    private const DISCOUNT_LABEL = 'Flat 20 percent off';
+    private const COUPON_CODE = 'SALE20';
+
+    /**
+     * @var CustomerTokenServiceInterface
+     */
+    private $customerTokenService;
+
+    /**
+     * @var DataFixtureStorage
+     */
+    private $fixtures;
+
+    /**
+     * @inheridoc
+     */
+    protected function setUp(): void
+    {
+        $this->customerTokenService = Bootstrap::getObjectManager()->get(CustomerTokenServiceInterface::class);
+        $this->fixtures = Bootstrap::getObjectManager()->get(DataFixtureStorageManager::class)->getStorage();
+    }
+
+    /**
+     * Test estimateTotals.discounts for virtual product
+     *
+     * @return void
+     * @throws AuthenticationException|LocalizedException
+     * @throws Exception
+     */
+    #[
+        DataFixture(
+            AddressConditionFixture::class,
+            [
+                'attribute' => 'total_qty',
+                'operator' => '>=',
+                'value' => 1
+            ],
+            'condition'
+        ),
+        DataFixture(
+            SalesRuleFixture::class,
+            [
+                'store_labels' => [1 => self::DISCOUNT_LABEL],
+                'coupon_type' => SalesRule::COUPON_TYPE_SPECIFIC,
+                'simple_action' => SalesRule::BY_PERCENT_ACTION,
+                'discount_amount' => self::DISCOUNT_PERCENTAGE,
+                'coupon_code' => self::COUPON_CODE,
+                'conditions' => ['$condition$'],
+                'uses_per_customer' => 1,
+                'stop_rules_processing' => true
+            ],
+            as: 'rule'
+        ),
+        DataFixture(ProductFixture::class, ['price' => self::PRODUCT_PRICE, 'type_id' => 'virtual'], as: 'product'),
+        DataFixture(CustomerFixture::class, as: 'customer'),
+        DataFixture(CustomerCartFixture::class, ['customer_id' => '$customer.id$'], as: 'quote'),
+        DataFixture(
+            AddProductToCartFixture::class,
+            [
+                'cart_id' => '$quote.id$',
+                'product_id' => '$product.id$',
+                'qty' => self::TOTAL_QTY
+            ]
+        ),
+        DataFixture(
+            ApplyCouponFixture::class,
+            [
+                'cart_id' => '$quote.id$',
+                'coupon_codes' => [self::COUPON_CODE]
+            ]
+        ),
+        DataFixture(SetBillingAddressFixture::class, ['cart_id' => '$quote.id$']),
+        DataFixture(QuoteIdMask::class, ['cart_id' => '$quote.id$'], 'quoteIdMask')
+    ]
+    public function testEstimateTotalsWithDiscount(): void
+    {
+        self::assertEquals(
+            [
+                'estimateTotals' => [
+                    'cart' => [
+                        'prices' => [
+                            'discounts' => [
+                                0 => [
+                                    'amount' => [
+                                        'value' => 20,
+                                        'currency' => "USD"
+                                    ],
+                                    'label' => self::DISCOUNT_LABEL,
+                                    'coupon' => [
+                                        'code' => self::COUPON_CODE
+                                    ],
+                                    'applied_to' => "ITEM"
+                                ]
+                            ]
+                        ]
+                    ]
+                ]
+            ],
+            $this->graphQlMutation(
+                $this->getEstimateTotalsMutation($this->fixtures->get('quoteIdMask')->getMaskedId()),
+                [],
+                '',
+                $this->getCustomerAuthHeaders($this->fixtures->get('customer')->getEmail())
+            )
+        );
+    }
+
+    /**
+     * Generates GraphQl mutation for estimateTotal with discounts
+     *
+     * @param string $maskedQuoteId
+     * @return string
+     */
+    private function getEstimateTotalsMutation(string $maskedQuoteId): string
+    {
+        return <<<MUTATION
+            mutation {
+                estimateTotals(
+                    input: {
+                        cart_id: "$maskedQuoteId"
+                        address: {
+                            country_code: US
+                            postcode: "36104"
+                            region: { region_code: "AL" }
+                        }
+                        shipping_method: {
+                            carrier_code: "flatrate",
+                            method_code: "flatrate"
+                        }
+                    }
+                ) {
+                    cart {
+                        prices {
+                            discounts {
+                                amount {
+                                    value
+                                    currency
+                                }
+                                label
+                                coupon {
+                                    code
+                                }
+                                applied_to
+                            }
+                        }
+                    }
+                }
+            }
+        MUTATION;
+    }
+
+    /**
+     * Returns the header with customer token for GQL Mutation
+     *
+     * @param string $email
+     * @return array
+     * @throws AuthenticationException
+     */
+    private function getCustomerAuthHeaders(string $email): array
+    {
+        $customerToken = $this->customerTokenService->createCustomerAccessToken($email, 'password');
+        return ['Authorization' => 'Bearer ' . $customerToken];
+    }
+}