webhooks/mention: Use proper message formatting.

zerver/webhooks/mention/tests.py

@@ -9,12 +9,14 @@ class MentionHookTests(WebhookTestCase):
 
     def test_mention_webfeed(self) -> None:
         expected_topic = u"news"
-        expected_message = (u"**[Historical Sexual Abuse (Football): 29 Nov 2016: House of Commons debates - TheyWorkForYou]"
-                            u"(https://www.theyworkforyou.com/debates/?id=2016-11-29b.1398.7&p=24887)**:\n"
-                            u"\u2026 Culture, Media and Sport\nNothing is more important than keeping children safe."
-                            u" Child sex abuse is an exceptionally vile crime, and all of Government take it very seriously indeed,"
-                            u" as I know this House does.\nChildren up and down the country are \u2026"
-                            )
+        expected_message = """
+**[Historical Sexual Abuse (Football): 29 Nov 2016: House of Commons debates - TheyWorkForYou](https://www.theyworkforyou.com/debates/?id=2016-11-29b.1398.7&p=24887)**:
+
+``` quote
+\u2026 Culture, Media and Sport\nNothing is more important than keeping children safe. Child sex abuse is an exceptionally vile crime, and all of Government take it very seriously indeed, as I know this House does.
+Children up and down the country are \u2026
+```
+""".strip()
 
         # use fixture named mention_webfeeds
         self.send_and_test_stream_message('webfeeds', expected_topic, expected_message,

zerver/webhooks/mention/view.py

@@ -19,7 +19,15 @@ def api_mention_webhook(
     source_url = payload["url"]
     description = payload["description"]
     # construct the body of the message
-    body = '**[%s](%s)**:\n%s' % (title, source_url, description)
+    template = """
+**[{title}]({url})**:
+
+``` quote
+{description}
+```
+""".strip()
+    body = template.format(title=title, url=source_url,
+                           description=description)
     topic = 'news'
 
     # send the message