diff --git a/lib/API/Endpoints/Newsletters.php b/lib/API/Endpoints/Newsletters.php
index 6c371956b4..bd61725c0f 100644
--- a/lib/API/Endpoints/Newsletters.php
+++ b/lib/API/Endpoints/Newsletters.php
@@ -247,13 +247,11 @@ class Newsletters extends APIEndpoint {
         APIError::NOT_FOUND => __('This newsletter does not exist.', 'mailpoet')
       ));
     } else {
-      $newsletter = $newsletter->asArray();
-
       $renderer = new Renderer($newsletter, $preview = true);
       $rendered_newsletter = $renderer->render();
       $divider = '***MailPoet***';
       $data_for_shortcodes = array_merge(
-        array($newsletter['subject']),
+        array($newsletter->subject),
         $rendered_newsletter
       );
 
@@ -266,19 +264,22 @@ class Newsletters extends APIEndpoint {
         $newsletter,
         $subscriber
       );
+
       list(
-        $newsletter['subject'],
-        $newsletter['body']['html'],
-        $newsletter['body']['text']
+        $rendered_newsletter['subject'],
+        $rendered_newsletter['body']['html'],
+        $rendered_newsletter['body']['text']
       ) = explode($divider, $shortcodes->replace($body));
 
       try {
-        $mailer = new \MailPoet\Mailer\Mailer(
-          $mailer = false,
-          $sender = false,
-          $reply_to = false
+        $mailer = (!empty($data['mailer'])) ?
+          $data['mailer'] :
+          new \MailPoet\Mailer\Mailer(
+            $mailer = false,
+            $sender = false,
+            $reply_to = false
         );
-        $result = $mailer->send($newsletter, $data['subscriber']);
+        $result = $mailer->send($rendered_newsletter, $data['subscriber']);
 
         if($result['response'] === false) {
           $error = sprintf(
diff --git a/tests/unit/API/Endpoints/NewslettersTest.php b/tests/unit/API/Endpoints/NewslettersTest.php
index 20b8d1ba9c..627ee053c6 100644
--- a/tests/unit/API/Endpoints/NewslettersTest.php
+++ b/tests/unit/API/Endpoints/NewslettersTest.php
@@ -1,4 +1,6 @@
 <?php
+use Codeception\Util\Fixtures;
+use Codeception\Util\Stub;
 use \MailPoet\API\Response as APIResponse;
 use \MailPoet\API\Endpoints\Newsletters;
 use \MailPoet\Models\Newsletter;
@@ -11,11 +13,13 @@ class NewslettersTest extends MailPoetTest {
   function _before() {
     $this->newsletter = Newsletter::createOrUpdate(array(
       'subject' => 'My Standard Newsletter',
-      'type' => Newsletter::TYPE_STANDARD
+      'body' => Fixtures::get('newsletter_subject_template'),
+      'type' => Newsletter::TYPE_STANDARD,
     ));
 
     $this->post_notification = Newsletter::createOrUpdate(array(
       'subject' => 'My Post Notification',
+      'body' => Fixtures::get('newsletter_subject_template'),
       'type' => Newsletter::TYPE_NOTIFICATION
     ));
   }
@@ -445,10 +449,31 @@ class NewslettersTest extends MailPoetTest {
     expect($response->meta['count'])->equals(0);
   }
 
+  function testItCanSendAPreview() {
+    $subscriber = 'test@subscriber.com';
+    $data = array(
+      'subscriber' => $subscriber,
+      'id' => $this->newsletter->id,
+      'mailer' => Stub::makeEmpty(
+        '\MailPoet\Mailer\Mailer',
+        array(
+          'send' => function($newsletter, $subscriber) {
+            expect(is_array($newsletter))->true();
+            expect($subscriber)->equals($subscriber);
+            return array('response' => true);
+          }
+        )
+      )
+    );
+    $router = new Newsletters();
+    $response = $router->sendPreview($data);
+    expect($response->status)->equals(APIResponse::STATUS_OK);
+  }
+
   function _after() {
     Newsletter::deleteMany();
     NewsletterSegment::deleteMany();
     NewsletterOptionField::deleteMany();
     Segment::deleteMany();
   }
-}
+}
\ No newline at end of file