diff --git a/zerver/tests/test_bugdown.py b/zerver/tests/test_bugdown.py
index 251955dac7..6eae5d1835 100644
--- a/zerver/tests/test_bugdown.py
+++ b/zerver/tests/test_bugdown.py
@@ -343,6 +343,15 @@ class BugdownTest(TestCase):
         self.assertEqual(converted, '<p>We should fix <a href="https://trac.zulip.net/ticket/224" target="_blank" title="https://trac.zulip.net/ticket/224">#224</a> and <a href="https://trac.zulip.net/ticket/115" target="_blank" title="https://trac.zulip.net/ticket/115">#115</a>, but not issue#124 or #1124z or <a href="https://trac.zulip.net/ticket/16" target="_blank" title="https://trac.zulip.net/ticket/16">trac #15</a> today.</p>')
         self.assertEqual(converted_subject,  [u'https://trac.zulip.net/ticket/444'])
 
+    def test_realm_patterns_negative(self):
+        realm = get_realm('zulip.com')
+        RealmFilter(realm=realm, pattern=r"#(?P<id>[0-9]{2,8})",
+                    url_format_string=r"https://trac.zulip.net/ticket/%(id)s").save()
+        boring_msg = Message(sender=get_user_profile_by_email("othello@zulip.com"),
+                             subject=u"no match here")
+        converted_boring_subject = bugdown.subject_links(realm.domain.lower(), boring_msg.subject)
+        self.assertEqual(converted_boring_subject,  [])
+
     def test_stream_subscribe_button_simple(self):
         msg = '!_stream_subscribe_button(simple)'
         converted = bugdown_convert(msg)