diff --git a/core/modules/comment/tests/src/Unit/CommentManagerTest.php b/core/modules/comment/tests/src/Unit/CommentManagerTest.php
index 1e1494c..234c459 100644
--- a/core/modules/comment/tests/src/Unit/CommentManagerTest.php
+++ b/core/modules/comment/tests/src/Unit/CommentManagerTest.php
@@ -3,6 +3,7 @@
 namespace Drupal\Tests\comment\Unit;
 
 use Drupal\comment\CommentManager;
+use Drupal\node\Entity\Node;
 use Drupal\Tests\UnitTestCase;
 
 /**
@@ -21,7 +22,7 @@ public function testGetFields() {
     $entity_type = $this->getMock('Drupal\Core\Entity\ContentEntityTypeInterface');
     $entity_type->expects($this->any())
       ->method('getClass')
-      ->will($this->returnValue('Node'));
+      ->will($this->returnValue(Node::class));
 
     $entity_manager = $this->getMock('Drupal\Core\Entity\EntityManagerInterface');