MC-32201: Reorder functionality

Author: Leonid Poluianov

dev/tests/api-functional/testsuite/Magento/GraphQl/Sales/ReorderTest.php

@@ -116,6 +116,41 @@ public function testSimpleProductOutOfStock()
         $this->assertWithDeletedProduct($productRepository, $product);
     }
 
+    /**
+     * Test reorder when simple product qty is 0, with allowed backorders configured to below 0
+     *
+     * @magentoConfigFixture admin_store cataloginventory/item_options/backorders 1
+     * @magentoConfigFixture admin_store cataloginventory/item_options/use_deferred_stock_update 0
+     * @magentoApiDataFixture Magento/Sales/_files/order_with_zero_qty_product.php
+     * @throws \Exception
+     */
+    public function testBackorderWithOutOfStock()
+    {
+        $response = $this->makeReorderForDefaultCustomer();
+        $expectedResponse = [
+            'userInputErrors' => [],
+            'cart' => [
+                'email' => 'customer@example.com',
+                'total_quantity' => 2,
+                'items' => [
+                    [
+                        'quantity' => 1,
+                        'product' => [
+                            'sku' => 'simple'
+                        ]
+                    ],
+                    [
+                        'quantity' => 1,
+                        'product' => [
+                            'sku' => 'simple-2'
+                        ]
+                    ]
+                ],
+            ],
+        ];
+        $this->assertResponseFields($response['reorderItems'], $expectedResponse);
+    }
+
     /**
      * Assert that simple product is not available.
      */

dev/tests/integration/testsuite/Magento/Sales/_files/order_with_zero_qty_product.php

@@ -0,0 +1,28 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+use Magento\TestFramework\Helper\Bootstrap;
+
+require __DIR__ . '/../../../Magento/Sales/_files/order_with_two_simple_products.php';
+
+$customerIdFromFixture = 1;
+/** @var $order \Magento\Sales\Model\Order */
+$order->setCustomerId($customerIdFromFixture)->setCustomerIsGuest(false)->save();
+
+// load product and set it out of stock
+/** @var \Magento\Catalog\Api\ProductRepositoryInterface $repository */
+$productRepository = Bootstrap::getObjectManager()->create(\Magento\Catalog\Api\ProductRepositoryInterface::class);
+$productSku = 'simple';
+/** @var \Magento\Catalog\Model\Product $product */
+$product = $productRepository->get($productSku);
+// set product qty to zero
+$product->setStockData(
+    [
+        'use_config_manage_stock'   => 1,
+        'qty'                       => 0,
+    ]
+);
+$productRepository->save($product);

dev/tests/integration/testsuite/Magento/Sales/_files/order_with_zero_qty_product_rollback.php

@@ -0,0 +1,7 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+require __DIR__ . '/../../../Magento/Sales/_files/order_with_two_simple_products_rollback.php';