Autoformat hyperlinks in Slack alerts

Format the Slack message using the "mrkdwn" type, which will make
hyperlinks clickable.

New test for Slack destination.

redash/destinations/slack.py

@@ -26,13 +26,13 @@ def notify(self, alert, query, user, new_state, app, host, metadata, options):
         fields = [
             {
                 "title": "Query",
+                "type": "mrkdwn",
                 "value": "{host}/queries/{query_id}".format(host=host, query_id=query.id),
-                "short": True,
             },
             {
                 "title": "Alert",
+                "type": "mrkdwn",
                 "value": "{host}/alerts/{alert_id}".format(host=host, alert_id=alert.id),
-                "short": True,
             },
         ]
         if alert.custom_body:

tests/handlers/test_destinations.py

@@ -5,6 +5,7 @@
 from redash.destinations.asana import Asana
 from redash.destinations.datadog import Datadog
 from redash.destinations.discord import Discord
+from redash.destinations.slack import Slack
 from redash.destinations.webex import Webex
 from redash.models import Alert, NotificationDestination
 from tests import BaseTestCase
@@ -201,6 +202,59 @@ def test_asana_notify_calls_requests_post():
         assert mock_response.status_code == 204
 
 
+def test_slack_notify_calls_requests_post():
+    alert = mock.Mock(spec_set=["id", "name", "custom_subject", "custom_body", "render_template"])
+    alert.id = 1
+    alert.name = "Test Alert"
+    alert.custom_subject = "Test custom subject"
+    alert.custom_body = "Test custom body"
+
+    alert.render_template = mock.Mock(return_value={"Rendered": "template"})
+    query = mock.Mock()
+    query.id = 1
+
+    user = mock.Mock()
+    app = mock.Mock()
+    host = "https://localhost:5000"
+    options = {"url": "https://slack.com/api/api.test"}
+    metadata = {"Scheduled": False}
+
+    new_state = Alert.TRIGGERED_STATE
+    destination = Slack(options)
+
+    with mock.patch("redash.destinations.slack.requests.post") as mock_post:
+        mock_response = mock.Mock()
+        mock_response.status_code = 204
+        mock_post.return_value = mock_response
+
+        destination.notify(alert, query, user, new_state, app, host, metadata, options)
+
+        query_link = f"{host}/queries/{query.id}"
+        alert_link = f"{host}/alerts/{alert.id}"
+
+        expected_payload = {
+            "attachments": [
+                {
+                    "text": "Test custom subject",
+                    "color": "#c0392b",
+                    "fields": [
+                        {"title": "Query", "type": "mrkdwn", "value": query_link},
+                        {"title": "Alert", "type": "mrkdwn", "value": alert_link},
+                        {"title": "Description", "value": "Test custom body"},
+                    ],
+                }
+            ]
+        }
+
+        mock_post.assert_called_once_with(
+            "https://slack.com/api/api.test",
+            data=json.dumps(expected_payload).encode(),
+            timeout=5.0,
+        )
+
+        assert mock_response.status_code == 204
+
+
 def test_webex_notify_calls_requests_post():
     alert = mock.Mock(spec_set=["id", "name", "custom_subject", "custom_body", "render_template"])
     alert.id = 1