diff --git a/spec/lib/advanced_text_formatter_spec.rb b/spec/lib/advanced_text_formatter_spec.rb
index 03cd229bf94551..465f508b9dd427 100644
--- a/spec/lib/advanced_text_formatter_spec.rb
+++ b/spec/lib/advanced_text_formatter_spec.rb
@@ -281,6 +281,14 @@
         end
       end
 
+      context 'with text containing a hashtag with underscores' do
+        let(:text) { '#_hashtag_' }
+
+        it 'creates a hashtag link' do
+          expect(subject).to include '/tags/_hashtag_" class="mention hashtag" rel="tag">#<span>_hashtag_</span></a>'
+        end
+      end
+
       context 'with text with a stand-alone xmpp: URI' do
         let(:text) { 'xmpp:user@instance.com' }