Update to Drupal 8.1.0. For more information, see https://www.drupal.org/drupal-8.1.0-release-notes

core/modules/rest/src/Tests/RESTTestBase.php

@@ -1,10 +1,5 @@
 <?php
 
-/**
- * @file
- * Contains \Drupal\rest\Tests\RESTTestBase.
- */
-
 namespace Drupal\rest\Tests;
 
 use Drupal\node\NodeInterface;
@@ -194,7 +189,9 @@ abstract class RESTTestBase extends WebTestBase {
    *   The new entity object.
    */
   protected function entityCreate($entity_type) {
-    return entity_create($entity_type, $this->entityValues($entity_type));
+    return $this->container->get('entity_type.manager')
+      ->getStorage($entity_type)
+      ->create($this->entityValues($entity_type));
   }
 
   /**