diff -u b/core/modules/system/tests/src/Functional/Menu/MenuLinkSecurityTest.php b/core/modules/system/tests/src/Functional/Menu/MenuLinkSecurityTest.php
--- b/core/modules/system/tests/src/Functional/Menu/MenuLinkSecurityTest.php
+++ b/core/modules/system/tests/src/Functional/Menu/MenuLinkSecurityTest.php
@@ -36,7 +36,7 @@
     $this->drupalPlaceBlock('system_menu_block:tools');
 
     $this->drupalGet('<front>');
-    $thBlockXssTest.phpis->assertSession()->responseNotContains('<script>alert("Wild animals")</script>');
+    $this->assertSession()->responseNotContains('<script>alert("Wild animals")</script>');
     $this->assertSession()->responseNotContains('<script>alert("Even more wild animals")</script>');
     $this->assertEscaped('<script>alert("Wild animals")</script>');
     $this->assertEscaped('<script>alert("Even more wild animals")</script>');