M2CE-30469: The tests and logic fixes

Author: andrewbess

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

@@ -89,7 +89,7 @@ public function resolve(
         }
         $currentUserId = $context->getUserId();
 
-        if (empty($args['destination_cart_id'])) {
+        if (!isset($args['destination_cart_id'])) {
             try {
                 $cart = $this->customerCartResolver->resolve($currentUserId);
             } catch (CouldNotSaveException $exception) {
@@ -101,6 +101,12 @@ public function resolve(
             $customerMaskedCartId = $this->quoteIdToMaskedQuoteId->execute(
                 (int) $cart->getId()
             );
+        } else {
+            if (empty($args['destination_cart_id'])) {
+                throw new GraphQlInputException(__(
+                    'The parameter "destination_cart_id" cannot be empty'
+                ));
+            }
         }
 
         $guestMaskedCartId = $args['source_cart_id'];

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

@@ -192,6 +192,9 @@ public function testMergeCartsWithEmptySourceCartId()
      */
     public function testMergeCartsWithEmptyDestinationCartId()
     {
+        $this->expectException(\Exception::class);
+        $this->expectExceptionMessage('The parameter "destination_cart_id" cannot be empty');
+
         $guestQuote = $this->quoteFactory->create();
         $this->quoteResource->load(
             $guestQuote,
@@ -206,6 +209,54 @@ public function testMergeCartsWithEmptyDestinationCartId()
         $this->graphQlMutation($query, [], '', $this->getHeaderMap());
     }
 
+    /**
+     * @magentoApiDataFixture Magento/Checkout/_files/quote_with_virtual_product_saved.php
+     * @magentoApiDataFixture Magento/Customer/_files/customer.php
+     * @magentoApiDataFixture Magento/GraphQl/Catalog/_files/simple_product.php
+     * @magentoApiDataFixture Magento/GraphQl/Quote/_files/customer/create_empty_cart.php
+     * @magentoApiDataFixture Magento/GraphQl/Quote/_files/add_simple_product.php
+     */
+    public function testMergeCartsWithoutDestinationCartId()
+    {
+        $guestQuote = $this->quoteFactory->create();
+        $this->quoteResource->load(
+            $guestQuote,
+            'test_order_with_virtual_product_without_address',
+            'reserved_order_id'
+        );
+        $guestQuoteMaskedId = $this->quoteIdToMaskedId->execute((int)$guestQuote->getId());
+        $query = $this->getCartMergeMutationWithoutDestinationCartId(
+            $guestQuoteMaskedId
+        );
+        $mergeResponse = $this->graphQlMutation($query, [], '', $this->getHeaderMap());
+
+        self::assertArrayHasKey('mergeCarts', $mergeResponse);
+        $cartResponse = $mergeResponse['mergeCarts'];
+        self::assertArrayHasKey('items', $cartResponse);
+        self::assertCount(2, $cartResponse['items']);
+
+        $customerQuote = $this->quoteFactory->create();
+        $this->quoteResource->load($customerQuote, 'test_quote', 'reserved_order_id');
+        $customerQuoteMaskedId = $this->quoteIdToMaskedId->execute((int)$customerQuote->getId());
+
+        $cartResponse = $this->graphQlMutation(
+            $this->getCartQuery($customerQuoteMaskedId),
+            [],
+            '',
+            $this->getHeaderMap()
+        );
+
+        self::assertArrayHasKey('cart', $cartResponse);
+        self::assertArrayHasKey('items', $cartResponse['cart']);
+        self::assertCount(2, $cartResponse['cart']['items']);
+        $item1 = $cartResponse['cart']['items'][0];
+        self::assertArrayHasKey('quantity', $item1);
+        self::assertEquals(2, $item1['quantity']);
+        $item2 = $cartResponse['cart']['items'][1];
+        self::assertArrayHasKey('quantity', $item2);
+        self::assertEquals(1, $item2['quantity']);
+    }
+
     /**
      * Add simple product to cart
      *
@@ -253,6 +304,31 @@ private function getCartMergeMutation(string $guestQuoteMaskedId, string $custom
 QUERY;
     }
 
+    /**
+     * Create the mergeCart mutation
+     *
+     * @param string $guestQuoteMaskedId
+     * @return string
+     */
+    private function getCartMergeMutationWithoutDestinationCartId(
+        string $guestQuoteMaskedId
+    ): string {
+        return <<<QUERY
+mutation {
+  mergeCarts(
+    source_cart_id: "{$guestQuoteMaskedId}"
+  ){
+  items {
+      quantity
+      product {
+        sku
+      }
+    }
+  }
+}
+QUERY;
+    }
+
     /**
      * Get cart query
      *