Ensure that invoice comments are returned when requested by GraphQL queries

app/code/Magento/Sales/Test/Fixture/InvoiceComment.php

@@ -0,0 +1,77 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\Sales\Test\Fixture;
+
+use Magento\Framework\DataObject;
+use Magento\Sales\Api\Data\CommentInterface;
+use Magento\Sales\Api\Data\EntityInterface;
+use Magento\Sales\Api\Data\InvoiceCommentInterface;
+use Magento\Sales\Api\InvoiceCommentRepositoryInterface;
+use Magento\TestFramework\Fixture\Api\ServiceFactory;
+use Magento\TestFramework\Fixture\RevertibleDataFixtureInterface;
+
+class InvoiceComment implements RevertibleDataFixtureInterface
+{
+    private const DEFAULT_DATA = [
+        InvoiceCommentInterface::IS_CUSTOMER_NOTIFIED => 0,
+        InvoiceCommentInterface::PARENT_ID => 0,
+        CommentInterface::COMMENT => 'Test Comment',
+        CommentInterface::IS_VISIBLE_ON_FRONT => 0,
+        EntityInterface::ENTITY_ID => 0,
+        EntityInterface::CREATED_AT => "0000-00-00 00:00:00",
+    ];
+
+    /**
+     * @var ServiceFactory
+     */
+    private $serviceFactory;
+
+    /**
+     * @var InvoiceCommentRepositoryInterface
+     */
+    private $invoiceCommentRepository;
+
+    /**
+     * @param ServiceFactory $serviceFactory
+     * @param InvoiceCommentRepositoryInterface $invoiceCommentRepository
+     */
+    public function __construct(
+        ServiceFactory $serviceFactory,
+        InvoiceCommentRepositoryInterface $invoiceCommentRepository
+    ) {
+        $this->serviceFactory = $serviceFactory;
+        $this->invoiceCommentRepository = $invoiceCommentRepository;
+    }
+
+    public function apply(array $data = []): ?DataObject
+    {
+        $service = $this->serviceFactory->create(InvoiceCommentRepositoryInterface::class, 'save');
+        $invoiceComment = $service->execute($this->prepareData($data));
+
+        return $this->invoiceCommentRepository->get($invoiceComment->getId());
+    }
+
+    public function revert(DataObject $data): void
+    {
+        $invoice = $this->invoiceCommentRepository->get($data->getId());
+        $this->invoiceCommentRepository->delete($invoice);
+    }
+
+    /**
+     * Prepare invoice data
+     *
+     * @param array $data
+     * @return array
+     */
+    private function prepareData(array $data): array
+    {
+        $data['entity'] = array_merge(self::DEFAULT_DATA, $data);
+
+        return $data;
+    }
+}

app/code/Magento/SalesGraphQl/Model/Resolver/Invoices.php

@@ -41,10 +41,31 @@ public function resolve(
             $invoices[] = [
                 'id' => base64_encode($invoice->getEntityId()),
                 'number' => $invoice['increment_id'],
+                'comments' => $this->getInvoiceComments($invoice),
                 'model' => $invoice,
                 'order' => $orderModel
             ];
         }
         return $invoices;
     }
+
+    /**
+     * Get invoice comments in proper format
+     *
+     * @param InvoiceInterface $invoice
+     * @return array
+     */
+    private function getInvoiceComments(InvoiceInterface $invoice): array
+    {
+        $comments = [];
+        foreach ($invoice->getComments() as $comment) {
+            if ($comment->getIsVisibleOnFront()) {
+                $comments[] = [
+                    'timestamp' => $comment->getCreatedAt(),
+                    'message' => $comment->getComment()
+                ];
+            }
+        }
+        return $comments;
+    }
 }

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

@@ -7,9 +7,23 @@
 
 namespace Magento\GraphQl\Sales;
 
+use Magento\Catalog\Test\Fixture\Product as ProductFixture;
+use Magento\Checkout\Test\Fixture\PlaceOrder as PlaceOrderFixture;
+use Magento\Checkout\Test\Fixture\SetBillingAddress as SetBillingAddressFixture;
+use Magento\Checkout\Test\Fixture\SetDeliveryMethod as SetDeliveryMethodFixture;
+use Magento\Checkout\Test\Fixture\SetGuestEmail as SetGuestEmailFixture;
+use Magento\Checkout\Test\Fixture\SetPaymentMethod as SetPaymentMethodFixture;
+use Magento\Checkout\Test\Fixture\SetShippingAddress as SetShippingAddressFixture;
+use Magento\Customer\Test\Fixture\Customer;
 use Magento\Framework\Registry;
+use Magento\Quote\Test\Fixture\AddProductToCart as AddProductToCartFixture;
+use Magento\Quote\Test\Fixture\CustomerCart;
+use Magento\Quote\Test\Fixture\GuestCart as GuestCartFixture;
 use Magento\Sales\Api\OrderRepositoryInterface;
 use Magento\Sales\Model\ResourceModel\Order\Collection;
+use Magento\Sales\Test\Fixture\Invoice as InvoiceFixture;
+use Magento\Sales\Test\Fixture\InvoiceComment as InvoiceCommentFixture ;
+use Magento\TestFramework\Fixture\DataFixture;
 use Magento\TestFramework\Helper\Bootstrap;
 use Magento\TestFramework\TestCase\GraphQlAbstract;
 use Magento\GraphQl\GetCustomerAuthenticationHeader;
@@ -410,6 +424,64 @@ public function testPartialInvoiceForCustomerWithTaxesAndDiscounts()
         $this->deleteOrder();
     }
 
+    #[
+        DataFixture(Customer::class, ['email' => 'customer@search.example.com'], as: 'customer'),
+        DataFixture(ProductFixture::class, as: 'product'),
+        DataFixture(CustomerCart::class, ['customer_id' => '$customer.id$'], as: 'cart'),
+        DataFixture(AddProductToCartFixture::class, ['cart_id' => '$cart.id$', 'product_id' => '$product.id$']),
+        DataFixture(SetBillingAddressFixture::class, ['cart_id' => '$cart.id$']),
+        DataFixture(SetShippingAddressFixture::class, ['cart_id' => '$cart.id$']),
+        DataFixture(SetGuestEmailFixture::class, ['cart_id' => '$cart.id$']),
+        DataFixture(SetDeliveryMethodFixture::class, ['cart_id' => '$cart.id$']),
+        DataFixture(SetPaymentMethodFixture::class, ['cart_id' => '$cart.id$']),
+        DataFixture(PlaceOrderFixture::class, ['cart_id' => '$cart.id$'], 'order'),
+        DataFixture(InvoiceFixture::class, ['order_id' => '$order.id$'], 'invoice'),
+        DataFixture(InvoiceCommentFixture::class, [
+            'parent_id' => '$invoice.id$',
+            'comment' => 'visible_comment',
+            'is_visible_on_front' => 1,
+        ]),
+        DataFixture(InvoiceCommentFixture::class, [
+            'parent_id' => '$invoice.id$',
+            'comment' => 'non_visible_comment',
+            'is_visible_on_front' => 0,
+        ]),
+    ]
+    public function testInvoiceCommentsQuery()
+    {
+        $query =
+            <<<QUERY
+{
+  customer {
+    orders {
+      items {
+        invoices {
+          comments {
+            message
+            timestamp
+          }
+        }
+      }
+    }
+  }
+}
+QUERY;
+
+        $currentEmail = 'customer@search.example.com';
+        $currentPassword = 'password';
+        $response = $this->graphQlQuery(
+            $query,
+            [],
+            '',
+            $this->customerAuthenticationHeader->execute($currentEmail, $currentPassword)
+        );
+
+        $invoice = $response['customer']['orders']['items'][0]['invoices'][0];
+        $this->assertCount(1, $invoice['comments']);
+        $this->assertEquals('visible_comment', $invoice['comments'][0]['message']);
+        $this->assertNotEmpty($invoice['comments'][0]['timestamp']);
+    }
+
     /**
      * Prepare invoice for the order
      *