1 files changed, 12 insertions, 0 deletions

diff --git a/spec/features/issues/user_comments_on_issue_spec.rb b/spec/features/issues/user_comments_on_issue_spec.rb
index ba5b80ed04b..b4b9a589ba3 100644
--- a/spec/features/issues/user_comments_on_issue_spec.rb
+++ b/spec/features/issues/user_comments_on_issue_spec.rb
@@ -40,6 +40,18 @@ describe "User comments on issue", :js do
 
       expect(page.find('pre code').text).to eq code_block_content
     end
+
+    it "does not render html content in mermaid" do
+      html_content = "<img onerror=location=`javascript\\u003aalert\\u0028document.domain\\u0029` src=x>"
+      mermaid_content = "graph LR\n  B-->D(#{html_content});"
+      comment = "```mermaid\n#{mermaid_content}\n```"
+
+      add_note(comment)
+
+      wait_for_requests
+
+      expect(page.find('svg.mermaid')).to have_content html_content
+    end
   end
 
   context "when editing comments" do