diff --git a/lib/Entities/NewsletterEntity.php b/lib/Entities/NewsletterEntity.php
index 8b2d17e729..4ecf5b5303 100644
--- a/lib/Entities/NewsletterEntity.php
+++ b/lib/Entities/NewsletterEntity.php
@@ -117,7 +117,7 @@ class NewsletterEntity {
    * @ORM\Column(type="string")
    * @var string
    */
-  private $ga_campaign;
+  private $ga_campaign = '';
 
   /**
    * @ORM\ManyToOne(targetEntity="MailPoet\Entities\NewsletterEntity")
diff --git a/lib/Newsletter/Renderer/Renderer.php b/lib/Newsletter/Renderer/Renderer.php
index 319180a6fd..0620ecf112 100644
--- a/lib/Newsletter/Renderer/Renderer.php
+++ b/lib/Newsletter/Renderer/Renderer.php
@@ -32,7 +32,7 @@ class Renderer {
     $this->blocks_renderer = new Blocks\Renderer($this->newsletter);
     $this->columns_renderer = new Columns\Renderer();
     $this->preprocessor = new Preprocessor($this->blocks_renderer, WPFunctions::get());
-    $this->CSS_inliner = new \MailPoet\Util\CSS();
+    $this->CSS_inliner = new \MailPoetVendor\CSS();
     $this->template = file_get_contents(dirname(__FILE__) . '/' . self::NEWSLETTER_TEMPLATE);
     $this->premium_activated = License::getLicense();
     $bridge = new Bridge();
diff --git a/lib/WooCommerce/TransactionalEmails.php b/lib/WooCommerce/TransactionalEmails.php
index 4e4975b54a..38ca884955 100644
--- a/lib/WooCommerce/TransactionalEmails.php
+++ b/lib/WooCommerce/TransactionalEmails.php
@@ -61,7 +61,7 @@ class TransactionalEmails {
     $saved_email_id = (bool)$this->settings->get(self::SETTING_EMAIL_ID, false);
     if (!$saved_email_id) {
       $email = $this->createNewsletter();
-      $this->settings->set(self::SETTING_EMAIL_ID, $email->id);
+      $this->settings->set(self::SETTING_EMAIL_ID, $email->getId());
     }
   }
 
@@ -103,9 +103,10 @@ class TransactionalEmails {
     $newsletter = new NewsletterEntity;
     $newsletter->setType(NewsletterEntity::TYPE_WC_TRANSACTIONAL_EMAIL);
     $newsletter->setSubject('WooCommerce Transactional Email');
-    $newsletter->setBody(json_encode($this->template->create($wc_email_settings)));
+    $newsletter->setBody($this->template->create($wc_email_settings));
     $this->newsletters_repository->persist($newsletter);
     $this->newsletters_repository->flush();
+    return $newsletter;
   }
 
   private function getNewsletter() {
diff --git a/tests/integration/WooCommerce/TransactionalEmailsTest.php b/tests/integration/WooCommerce/TransactionalEmailsTest.php
index cdd1a102a0..c542da59f8 100644
--- a/tests/integration/WooCommerce/TransactionalEmailsTest.php
+++ b/tests/integration/WooCommerce/TransactionalEmailsTest.php
@@ -4,6 +4,7 @@ namespace MailPoet\WooCommerce;
 
 use Codeception\Stub;
 use MailPoet\DI\ContainerWrapper;
+use MailPoet\Entities\NewsletterEntity;
 use MailPoet\Models\Newsletter;
 use MailPoet\Newsletter\Editor\LayoutHelper as L;
 use MailPoet\Newsletter\NewslettersRepository;
@@ -26,32 +27,36 @@ class TransactionalEmailsTest extends \MailPoetTest {
   /** @var TransactionalEmails */
   private $transactional_emails;
 
+  /** @var NewslettersRepository */
+  private $newsletters_repository;
+
   function _before() {
     $this->wp = new WPFunctions();
     $this->settings = SettingsController::getInstance();
     $this->original_wc_settings = $this->settings->get('woocommerce');
+    $this->newsletters_repository = ContainerWrapper::getInstance()->get(NewslettersRepository::class);
     $this->transactional_emails = new TransactionalEmails(
       $this->wp,
       $this->settings,
       ContainerWrapper::getInstance()->get(Template::class),
       ContainerWrapper::getInstance()->get(Renderer::class),
-      ContainerWrapper::getInstance()->get(NewslettersRepository::class)
+      $this->newsletters_repository
     );
   }
 
   function testInitCreatesTransactionalEmailAndSavesItsId() {
     $this->transactional_emails->init();
-    $email = Newsletter::where('type', Newsletter::TYPE_WC_TRANSACTIONAL_EMAIL)->findOne();
+    $email = $this->newsletters_repository->findOneBy(['type' => Newsletter::TYPE_WC_TRANSACTIONAL_EMAIL]);
     $id = $this->settings->get(TransactionalEmails::SETTING_EMAIL_ID, null);
     expect($email)->notEmpty();
     expect($id)->notNull();
-    expect($email->id)->equals($id);
+    expect($email->getId())->equals($id);
   }
 
   function testInitDoesntCreateTransactionalEmailIfSettingAlreadySet() {
     $this->settings->set(TransactionalEmails::SETTING_EMAIL_ID, 1);
     $this->transactional_emails->init();
-    $email = Newsletter::where('type', Newsletter::TYPE_WC_TRANSACTIONAL_EMAIL)->findOne();
+    $email = $this->newsletters_repository->findOneBy(['type' => Newsletter::TYPE_WC_TRANSACTIONAL_EMAIL]);
     expect($email)->equals(null);
   }
 
@@ -66,32 +71,34 @@ class TransactionalEmailsTest extends \MailPoetTest {
       $this->settings,
       ContainerWrapper::getInstance()->get(Template::class),
       ContainerWrapper::getInstance()->get(Renderer::class),
-      ContainerWrapper::getInstance()->get(NewslettersRepository::class)
+      $this->newsletters_repository
     );
     $transactional_emails->init();
-    $email = Newsletter::where('type', Newsletter::TYPE_WC_TRANSACTIONAL_EMAIL)->findOne();
+    $email = $this->newsletters_repository->findOneBy([
+      'type' => NewsletterEntity::TYPE_WC_TRANSACTIONAL_EMAIL,
+    ]);
     expect($email)->notEmpty();
-    expect($email->body)->contains('my-awesome-image-url');
+    expect(json_encode($email->getBody()))->contains('my-awesome-image-url');
   }
 
   function testUseTemplateForWCEmails() {
     $added_actions = [];
     $removed_actions = [];
-    $newsletter = Newsletter::createOrUpdate([
-      'type' => Newsletter::TYPE_WC_TRANSACTIONAL_EMAIL,
-      'subject' => 'WooCommerce Transactional Email',
-      'preheader' => '',
-      'body' => json_encode([
-        'content' => L::col([
-          L::row([L::col([['type' => 'text', 'text' => 'Some text before heading']])]),
-          ['type' => 'woocommerceHeading'],
-          L::row([L::col([['type' => 'text', 'text' => 'Some text between heading and content']])]),
-          ['type' => 'woocommerceContent'],
-          L::row([L::col([['type' => 'text', 'text' => 'Some text after content']])]),
-        ]),
+    $newsletter = new NewsletterEntity;
+    $newsletter->setType(Newsletter::TYPE_WC_TRANSACTIONAL_EMAIL);
+    $newsletter->setSubject('WooCommerce Transactional Email');
+    $newsletter->setBody([
+      'content' => L::col([
+        L::row([L::col([['type' => 'text', 'text' => 'Some text before heading']])]),
+        ['type' => 'woocommerceHeading'],
+        L::row([L::col([['type' => 'text', 'text' => 'Some text between heading and content']])]),
+        ['type' => 'woocommerceContent'],
+        L::row([L::col([['type' => 'text', 'text' => 'Some text after content']])]),
       ]),
     ]);
-    $this->settings->set(TransactionalEmails::SETTING_EMAIL_ID, $newsletter->id);
+    $this->newsletters_repository->persist($newsletter);
+    $this->newsletters_repository->flush();
+    $this->settings->set(TransactionalEmails::SETTING_EMAIL_ID, $newsletter->getId());
     $wp = Stub::make(new WPFunctions, [
       'getOption' => function($name) {
         return '';
@@ -105,7 +112,7 @@ class TransactionalEmailsTest extends \MailPoetTest {
     ]);
     $renderer = Stub::make(Renderer::class, [
       'render' => function($email) use(&$newsletter) {
-        expect($email->id)->equals($newsletter->id);
+        expect($email->id)->equals($newsletter->getId());
       },
       'getHTMLBeforeContent' => function($heading_text) {
         return 'HTML before content with ' . $heading_text;
@@ -144,7 +151,12 @@ class TransactionalEmailsTest extends \MailPoetTest {
   }
 
   function _after() {
-    ORM::raw_execute('TRUNCATE ' . Newsletter::$_table);
+    $this->entity_manager
+      ->createQueryBuilder()
+      ->delete()
+      ->from(NewsletterEntity::class, 'n')
+      ->getQuery()
+      ->execute();
     $this->settings->set('woocommerce', $this->original_wc_settings);
   }
 }