GraphQL-172: GraphQL modules delivery

-- add block_rollback fixture

dev/tests/integration/testsuite/Magento/Cms/_files/block_rollback.php

@@ -0,0 +1,30 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+use Magento\Cms\Api\BlockRepositoryInterface;
+use Magento\Cms\Api\Data\BlockInterface;
+use Magento\Framework\Api\SearchCriteriaBuilder;
+use Magento\TestFramework\Helper\Bootstrap;
+
+$objectManager = Bootstrap::getObjectManager();
+
+/** @var BlockRepositoryInterface $blockRepository */
+$blockRepository = $objectManager->get(BlockRepositoryInterface::class);
+
+/** @var SearchCriteriaBuilder $searchCriteriaBuilder */
+$searchCriteriaBuilder = $objectManager->get(SearchCriteriaBuilder::class);
+$searchCriteria = $searchCriteriaBuilder->addFilter(BlockInterface::IDENTIFIER, 'fixture_block')
+    ->create();
+$result = $blockRepository->getList($searchCriteria);
+
+/**
+ * Tests which are wrapped with MySQL transaction clear all data by transaction rollback.
+ * In that case there is "if" which checks that "fixture_block" still exists in database.
+ */
+foreach ($result->getItems() as $item) {
+    $blockRepository->delete($item);
+}