diff --git a/core/modules/text/lib/Drupal/text/Tests/Formatter/TextPlainUnitTest.php b/core/modules/text/lib/Drupal/text/Tests/Formatter/TextPlainUnitTest.php
index f7d326a..6ccd60c 100644
--- a/core/modules/text/lib/Drupal/text/Tests/Formatter/TextPlainUnitTest.php
+++ b/core/modules/text/lib/Drupal/text/Tests/Formatter/TextPlainUnitTest.php
@@ -123,7 +123,7 @@ protected function createEntity($values = array()) {
    */
   protected function renderEntityFields(EntityInterface $entity, EntityViewDisplayInterface $display) {
     $content = $display->view($entity);
-    $this->drupalSetContent(drupal_render($content));
+    $this->content = drupal_render($content);
     return $this->content;
   }