diff --git a/dev/tests/integration/testsuite/Magento/AdminNotification/Controller/Adminhtml/Notification/MarkAsReadTest.php b/app/code/Magento/AdminNotification/Test/Integration/Controller/Adminhtml/Notification/MarkAsReadTest.php
similarity index 63%
rename from dev/tests/integration/testsuite/Magento/AdminNotification/Controller/Adminhtml/Notification/MarkAsReadTest.php
rename to app/code/Magento/AdminNotification/Test/Integration/Controller/Adminhtml/Notification/MarkAsReadTest.php
index ca2033b2efda2..dc52e60c3b4c2 100644
--- a/dev/tests/integration/testsuite/Magento/AdminNotification/Controller/Adminhtml/Notification/MarkAsReadTest.php
+++ b/app/code/Magento/AdminNotification/Test/Integration/Controller/Adminhtml/Notification/MarkAsReadTest.php
@@ -1,24 +1,29 @@
 <?php
-/***
+
+declare(strict_types=1);
+
+/**
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
-namespace Magento\AdminNotification\Controller\Adminhtml\Notification;
+namespace Magento\AdminNotification\Test\Integration\Controller\Adminhtml\Notification;
+
+use Magento\TestFramework\TestCase\AbstractBackendController;
 
 /**
  * Testing markAsRead controller.
  *
  * @magentoAppArea adminhtml
  */
-class MarkAsReadTest extends \Magento\TestFramework\TestCase\AbstractBackendController
+class MarkAsReadTest extends AbstractBackendController
 {
     /**
      * @inheritdoc
      */
     protected function setUp(): void
     {
+        parent::setUp();
         $this->resource = 'Magento_AdminNotification::mark_as_read';
         $this->uri = 'backend/admin/notification/markasread';
-        parent::setUp();
     }
 }
diff --git a/dev/tests/integration/testsuite/Magento/AdminNotification/Controller/Adminhtml/Notification/MassMarkAsReadTest.php b/app/code/Magento/AdminNotification/Test/Integration/Controller/Adminhtml/Notification/MassMarkAsReadTest.php
similarity index 53%
rename from dev/tests/integration/testsuite/Magento/AdminNotification/Controller/Adminhtml/Notification/MassMarkAsReadTest.php
rename to app/code/Magento/AdminNotification/Test/Integration/Controller/Adminhtml/Notification/MassMarkAsReadTest.php
index ea5fd8ec72ab1..b0155ae985e22 100644
--- a/dev/tests/integration/testsuite/Magento/AdminNotification/Controller/Adminhtml/Notification/MassMarkAsReadTest.php
+++ b/app/code/Magento/AdminNotification/Test/Integration/Controller/Adminhtml/Notification/MassMarkAsReadTest.php
@@ -1,19 +1,28 @@
 <?php
-/***
+
+declare(strict_types=1);
+
+/**
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
-namespace Magento\AdminNotification\Controller\Adminhtml\Notification;
+namespace Magento\AdminNotification\Test\Integration\Controller\Adminhtml\Notification;
 
 use Magento\Framework\App\Request\Http as HttpRequest;
+use Magento\Framework\Exception\AuthenticationException;
+use Magento\TestFramework\TestCase\AbstractBackendController;
 
-class MassMarkAsReadTest extends \Magento\TestFramework\TestCase\AbstractBackendController
+class MassMarkAsReadTest extends AbstractBackendController
 {
+    /**
+     * @return void
+     * @throws AuthenticationException
+     */
     protected function setUp(): void
     {
+        parent::setUp();
         $this->resource = 'Magento_AdminNotification::mark_as_read';
         $this->uri = 'backend/admin/notification/massmarkasread';
         $this->httpMethod = HttpRequest::METHOD_POST;
-        parent::setUp();
     }
 }
diff --git a/dev/tests/integration/testsuite/Magento/AdminNotification/Controller/Adminhtml/Notification/MassRemoveTest.php b/app/code/Magento/AdminNotification/Test/Integration/Controller/Adminhtml/Notification/MassRemoveTest.php
similarity index 54%
rename from dev/tests/integration/testsuite/Magento/AdminNotification/Controller/Adminhtml/Notification/MassRemoveTest.php
rename to app/code/Magento/AdminNotification/Test/Integration/Controller/Adminhtml/Notification/MassRemoveTest.php
index 06ccf4bb8a4af..ba9e9cf01e971 100644
--- a/dev/tests/integration/testsuite/Magento/AdminNotification/Controller/Adminhtml/Notification/MassRemoveTest.php
+++ b/app/code/Magento/AdminNotification/Test/Integration/Controller/Adminhtml/Notification/MassRemoveTest.php
@@ -1,19 +1,28 @@
 <?php
-/***
+
+declare(strict_types=1);
+
+/**
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
-namespace Magento\AdminNotification\Controller\Adminhtml\Notification;
+namespace Magento\AdminNotification\Test\Integration\Controller\Adminhtml\Notification;
 
 use Magento\Framework\App\Request\Http as HttpRequest;
+use Magento\Framework\Exception\AuthenticationException;
+use Magento\TestFramework\TestCase\AbstractBackendController;
 
-class MassRemoveTest extends \Magento\TestFramework\TestCase\AbstractBackendController
+class MassRemoveTest extends AbstractBackendController
 {
+    /**
+     * @return void
+     * @throws AuthenticationException
+     */
     protected function setUp(): void
     {
+        parent::setUp();
         $this->resource = 'Magento_AdminNotification::adminnotification_remove';
         $this->uri = 'backend/admin/notification/massremove';
         $this->httpMethod = HttpRequest::METHOD_POST;
-        parent::setUp();
     }
 }
diff --git a/app/code/Magento/AdminNotification/Test/Integration/Controller/Adminhtml/Notification/RemoveTest.php b/app/code/Magento/AdminNotification/Test/Integration/Controller/Adminhtml/Notification/RemoveTest.php
new file mode 100644
index 0000000000000..98cb38afa6dfc
--- /dev/null
+++ b/app/code/Magento/AdminNotification/Test/Integration/Controller/Adminhtml/Notification/RemoveTest.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\AdminNotification\Test\Integration\Controller\Adminhtml\Notification;
+
+use Magento\Framework\Exception\AuthenticationException;
+use Magento\TestFramework\TestCase\AbstractBackendController;
+
+class RemoveTest extends AbstractBackendController
+{
+    /**
+     * @return void
+     * @throws AuthenticationException
+     */
+    protected function setUp(): void
+    {
+        parent::setUp();
+        $this->resource = 'Magento_AdminNotification::adminnotification_remove';
+        $this->uri = 'backend/admin/notification/remove';
+    }
+}
diff --git a/app/code/Magento/AdminNotification/Test/Integration/Model/ResourceModel/Inbox/Collection/CriticalTest.php b/app/code/Magento/AdminNotification/Test/Integration/Model/ResourceModel/Inbox/Collection/CriticalTest.php
new file mode 100644
index 0000000000000..5bf6a27675d74
--- /dev/null
+++ b/app/code/Magento/AdminNotification/Test/Integration/Model/ResourceModel/Inbox/Collection/CriticalTest.php
@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\AdminNotification\Test\Integration\Model\ResourceModel\Inbox\Collection;
+
+use Magento\AdminNotification\Model\ResourceModel\Inbox\Collection\Critical;
+use Magento\TestFramework\Helper\Bootstrap;
+use PHPUnit\Framework\TestCase;
+
+class CriticalTest extends TestCase
+{
+    /**
+     * @var Critical
+     */
+    private $model;
+
+    /**
+     * @return void
+     */
+    protected function setUp(): void
+    {
+        $this->model = Bootstrap::getObjectManager()->create(
+            Critical::class
+        );
+    }
+
+    /**
+     * @magentoDataFixture Magento_AdminNotification::Test/Integration/_files/notifications.php
+     *
+     * @return void
+     */
+    public function testCollectionContainsLastUnreadCriticalItem(): void
+    {
+        $items = array_values($this->model->getItems());
+        $this->assertEquals('Unread Critical 3', $items[0]->getTitle());
+    }
+}
diff --git a/app/code/Magento/AdminNotification/Test/Integration/_files/notifications.php b/app/code/Magento/AdminNotification/Test/Integration/_files/notifications.php
new file mode 100644
index 0000000000000..d62914d6902de
--- /dev/null
+++ b/app/code/Magento/AdminNotification/Test/Integration/_files/notifications.php
@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+use Magento\AdminNotification\Model\Inbox;
+use Magento\Framework\Notification\MessageInterface;
+use Magento\TestFramework\Helper\Bootstrap;
+
+$om = Bootstrap::getObjectManager();
+$message = $om->create(Inbox::class);
+$message
+    ->setSeverity(MessageInterface::SEVERITY_CRITICAL)
+    ->setTitle('Unread Critical 1')
+    ->save();
+
+$message = $om->create(Inbox::class);
+$message
+    ->setSeverity(MessageInterface::SEVERITY_MAJOR)
+    ->setTitle('Unread Major 1')
+    ->save();
+
+$message = $om->create(Inbox::class);
+$message
+    ->setSeverity(MessageInterface::SEVERITY_CRITICAL)
+    ->setTitle('Unread Critical 2')
+    ->save();
+
+$message = $om->create(Inbox::class);
+$message
+    ->setSeverity(MessageInterface::SEVERITY_CRITICAL)
+    ->setTitle('Unread Critical 3')
+    ->save();
+
+$message = $om->create(Inbox::class);
+$message
+    ->setSeverity(MessageInterface::SEVERITY_CRITICAL)
+    ->setTitle('Read Critical 1')
+    ->setIsRead(1)
+    ->save();
+
+$message = $om->create(Inbox::class);
+$message
+    ->setSeverity(MessageInterface::SEVERITY_MAJOR)
+    ->setTitle('Unread Major 2')
+    ->save();
+
+$message = $om->create(Inbox::class);
+$message
+    ->setSeverity(MessageInterface::SEVERITY_CRITICAL)
+    ->setTitle('Removed Critical 1')
+    ->setIsRemove(1)
+    ->save();
diff --git a/dev/tests/integration/testsuite/Magento/Rss/Controller/Feed/IndexTest.php b/app/code/Magento/Rss/Test/Integration/Controller/Feed/IndexTest.php
similarity index 62%
rename from dev/tests/integration/testsuite/Magento/Rss/Controller/Feed/IndexTest.php
rename to app/code/Magento/Rss/Test/Integration/Controller/Feed/IndexTest.php
index 991914460c61b..19b09433ef790 100644
--- a/dev/tests/integration/testsuite/Magento/Rss/Controller/Feed/IndexTest.php
+++ b/app/code/Magento/Rss/Test/Integration/Controller/Feed/IndexTest.php
@@ -5,22 +5,29 @@
  */
 declare(strict_types=1);
 
-namespace Magento\Rss\Controller\Feed;
+namespace Magento\Rss\Test\Integration\Controller\Feed;
 
-class IndexTest extends \Magento\TestFramework\TestCase\AbstractBackendController
+use Magento\Customer\Api\CustomerRepositoryInterface;
+use Magento\Customer\Model\Session;
+use Magento\Framework\Exception\AuthenticationException;
+use Magento\Rss\Model\UrlBuilder;
+use Magento\TestFramework\TestCase\AbstractBackendController;
+use Magento\Wishlist\Model\Wishlist;
+
+class IndexTest extends AbstractBackendController
 {
     /**
-     * @var \Magento\Rss\Model\UrlBuilder
+     * @var UrlBuilder
      */
     private $urlBuilder;
 
     /**
-     * @var \Magento\Customer\Api\CustomerRepositoryInterface
+     * @var CustomerRepositoryInterface
      */
     private $customerRepository;
 
     /**
-     * @var \Magento\Wishlist\Model\Wishlist
+     * @var Wishlist
      */
     private $wishlist;
 
@@ -29,15 +36,19 @@ class IndexTest extends \Magento\TestFramework\TestCase\AbstractBackendControlle
      */
     private $customerSession;
 
+    /**
+     * @return void
+     * @throws AuthenticationException
+     */
     protected function setUp(): void
     {
         parent::setUp();
-        $this->urlBuilder = $this->_objectManager->get(\Magento\Rss\Model\UrlBuilder::class);
+        $this->urlBuilder = $this->_objectManager->get(UrlBuilder::class);
         $this->customerRepository = $this->_objectManager->get(
-            \Magento\Customer\Api\CustomerRepositoryInterface::class
+            CustomerRepositoryInterface::class
         );
-        $this->wishlist = $this->_objectManager->get(\Magento\Wishlist\Model\Wishlist::class);
-        $this->customerSession = $this->_objectManager->get(\Magento\Customer\Model\Session::class);
+        $this->wishlist = $this->_objectManager->get(Wishlist::class);
+        $this->customerSession = $this->_objectManager->get(Session::class);
     }
 
     /**
@@ -48,13 +59,13 @@ protected function setUp(): void
      * @magentoConfigFixture current_store rss/wishlist/active 1
      * @magentoConfigFixture current_store rss/config/active 1
      */
-    public function testRssResponse()
+    public function testRssResponse(): void
     {
         $firstCustomerId = 1;
         $this->customerSession->setCustomerId($firstCustomerId);
         $customer = $this->customerRepository->getById($firstCustomerId);
         $customerEmail = $customer->getEmail();
-        $wishlistId = $this->wishlist->loadByCustomerId($firstCustomerId)->getId();
+        $wishlistId = (int) $this->wishlist->loadByCustomerId($firstCustomerId)->getId();
         $this->dispatch($this->getLink($firstCustomerId, $customerEmail, $wishlistId));
         $body = $this->getResponse()->getBody();
         $this->assertStringContainsString('<title>John Smith\'s Wishlist</title>', $body);
@@ -68,22 +79,28 @@ public function testRssResponse()
      * @magentoConfigFixture current_store rss/wishlist/active 1
      * @magentoConfigFixture current_store rss/config/active 1
      */
-    public function testRssResponseWithIncorrectWishlistId()
+    public function testRssResponseWithIncorrectWishlistId(): void
     {
         $firstCustomerId = 1;
         $secondCustomerId = 2;
         $this->customerSession->setCustomerId($firstCustomerId);
         $customer = $this->customerRepository->getById($firstCustomerId);
         $customerEmail = $customer->getEmail();
-        $wishlistId = $this->wishlist->loadByCustomerId($secondCustomerId, true)->getId();
+        $wishlistId = (int) $this->wishlist->loadByCustomerId($secondCustomerId, true)->getId();
         $this->dispatch($this->getLink($firstCustomerId, $customerEmail, $wishlistId));
         $body = $this->getResponse()->getBody();
         $this->assertStringContainsString('<title>404 Not Found</title>', $body);
     }
 
-    private function getLink($customerId, $customerEmail, $wishlistId)
+    /**
+     * @param int $customerId
+     * @param string $customerEmail
+     * @param int $wishlistId
+     *
+     * @return string
+     */
+    private function getLink(int $customerId, string $customerEmail, int $wishlistId): string
     {
-
         return 'rss/feed/index/type/wishlist/data/'
             . base64_encode($customerId . ',' . $customerEmail)
             . '/wishlist_id/' . $wishlistId;
diff --git a/dev/tests/integration/testsuite/Magento/AdminNotification/Controller/Adminhtml/Notification/RemoveTest.php b/dev/tests/integration/testsuite/Magento/AdminNotification/Controller/Adminhtml/Notification/RemoveTest.php
deleted file mode 100644
index 0ffdbdd570f9c..0000000000000
--- a/dev/tests/integration/testsuite/Magento/AdminNotification/Controller/Adminhtml/Notification/RemoveTest.php
+++ /dev/null
@@ -1,16 +0,0 @@
-<?php
-/***
- * Copyright © Magento, Inc. All rights reserved.
- * See COPYING.txt for license details.
- */
-namespace Magento\AdminNotification\Controller\Adminhtml\Notification;
-
-class RemoveTest extends \Magento\TestFramework\TestCase\AbstractBackendController
-{
-    protected function setUp(): void
-    {
-        $this->resource = 'Magento_AdminNotification::adminnotification_remove';
-        $this->uri = 'backend/admin/notification/remove';
-        parent::setUp();
-    }
-}
diff --git a/dev/tests/integration/testsuite/Magento/AdminNotification/Model/ResourceModel/Inbox/Collection/CriticalTest.php b/dev/tests/integration/testsuite/Magento/AdminNotification/Model/ResourceModel/Inbox/Collection/CriticalTest.php
deleted file mode 100644
index 218bb5089ce3f..0000000000000
--- a/dev/tests/integration/testsuite/Magento/AdminNotification/Model/ResourceModel/Inbox/Collection/CriticalTest.php
+++ /dev/null
@@ -1,30 +0,0 @@
-<?php
-/**
- * Copyright © Magento, Inc. All rights reserved.
- * See COPYING.txt for license details.
- */
-namespace Magento\AdminNotification\Model\ResourceModel\Inbox\Collection;
-
-class CriticalTest extends \PHPUnit\Framework\TestCase
-{
-    /**
-     * @var \Magento\AdminNotification\Model\ResourceModel\Inbox\Collection\Critical
-     */
-    protected $_model;
-
-    protected function setUp(): void
-    {
-        $this->_model = \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create(
-            \Magento\AdminNotification\Model\ResourceModel\Inbox\Collection\Critical::class
-        );
-    }
-
-    /**
-     * @magentoDataFixture Magento/AdminNotification/_files/notifications.php
-     */
-    public function testCollectionContainsLastUnreadCriticalItem()
-    {
-        $items = array_values($this->_model->getItems());
-        $this->assertEquals('Unread Critical 3', $items[0]->getTitle());
-    }
-}
diff --git a/dev/tests/integration/testsuite/Magento/AdminNotification/_files/notifications.php b/dev/tests/integration/testsuite/Magento/AdminNotification/_files/notifications.php
deleted file mode 100644
index 0a8f2670b5740..0000000000000
--- a/dev/tests/integration/testsuite/Magento/AdminNotification/_files/notifications.php
+++ /dev/null
@@ -1,50 +0,0 @@
-<?php
-/**
- * Copyright © Magento, Inc. All rights reserved.
- * See COPYING.txt for license details.
- */
-
-declare(strict_types=1);
-
-use Magento\AdminNotification\Model\Inbox;
-use Magento\AdminNotification\Model\ResourceModel\Inbox as InboxResource;
-use Magento\Framework\Notification\MessageInterface;
-use Magento\Framework\ObjectManagerInterface;
-use Magento\TestFramework\Helper\Bootstrap;
-
-/** @var ObjectManagerInterface $objectManager */
-$objectManager = Bootstrap::getObjectManager();
-
-/**
- * @var Inbox $message
- * @var InboxResource $messageResource
- */
-$message = $objectManager->create(Inbox::class);
-$messageResource = $objectManager->create(InboxResource::class);
-
-$message->setSeverity(MessageInterface::SEVERITY_CRITICAL)->setTitle('Unread Critical 1');
-$messageResource->save($message);
-
-$message = $objectManager->create(Inbox::class);
-$message->setSeverity(MessageInterface::SEVERITY_MAJOR)->setTitle('Unread Major 1');
-$messageResource->save($message);
-
-$message = $objectManager->create(Inbox::class);
-$message->setSeverity(MessageInterface::SEVERITY_CRITICAL)->setTitle('Unread Critical 2');
-$messageResource->save($message);
-
-$message = $objectManager->create(Inbox::class);
-$message->setSeverity(MessageInterface::SEVERITY_CRITICAL)->setTitle('Unread Critical 3');
-$messageResource->save($message);
-
-$message = $objectManager->create(Inbox::class);
-$message->setSeverity(MessageInterface::SEVERITY_CRITICAL)->setTitle('Read Critical 1')->setIsRead(1);
-$messageResource->save($message);
-
-$message = $objectManager->create(Inbox::class);
-$message->setSeverity(MessageInterface::SEVERITY_MAJOR)->setTitle('Unread Major 2');
-$messageResource->save($message);
-
-$message = $objectManager->create(Inbox::class);
-$message->setSeverity(MessageInterface::SEVERITY_CRITICAL)->setTitle('Removed Critical 1')->setIsRemove(1);
-$messageResource->save($message);