diff --git a/core/modules/forum/src/Tests/ForumTest.php b/core/modules/forum/src/Tests/ForumTest.php
index 974e400..c81828e 100644
--- a/core/modules/forum/src/Tests/ForumTest.php
+++ b/core/modules/forum/src/Tests/ForumTest.php
@@ -514,6 +514,9 @@ function testForumWithNewPost() {
     // Check that forum renders properly.
     $this->drupalGet("forum/{$this->forum['tid']}");
     $this->assertResponse(200);
+
+    // Verify there is no unintentional HTML tag escaping.
+    $this->assertNoEscaped('<', '');
   }
 
   /**