diff --git a/CHANGELOG.md b/CHANGELOG.md
index 78b8aea2..4c2169a0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ All notable changes to this project will be documented in this file.
 - Fix List-Unsubscribe email header value: add angle brackets
 - Unsubscribe links serve a form, and require HTTP POST to actually unsubscribe
 - For webhook integration, validate each header line separately
+- Fix "Send Test Notification" for webhooks that only fire on checks going up
 
 
 ## v1.11.0 - 2019-11-22
diff --git a/hc/api/transports.py b/hc/api/transports.py
index 7f53cff9..749bc0cf 100644
--- a/hc/api/transports.py
+++ b/hc/api/transports.py
@@ -221,7 +221,8 @@ class Webhook(HttpTransport):
 
     def notify(self, check):
         spec = self.channel.webhook_spec(check.status)
-        assert spec["url"]
+        if not spec["url"]:
+            return "Empty webhook URL"
 
         url = self.prepare(spec["url"], check, urlencode=True)
         headers = {}
diff --git a/hc/front/tests/test_send_test_notification.py b/hc/front/tests/test_send_test_notification.py
index 6ddec998..0b95aca1 100644
--- a/hc/front/tests/test_send_test_notification.py
+++ b/hc/front/tests/test_send_test_notification.py
@@ -1,6 +1,9 @@
+import json
+
 from django.core import mail
 from hc.api.models import Channel
 from hc.test import BaseTestCase
+from mock import patch
 
 
 class SendTestNotificationTestCase(BaseTestCase):
@@ -27,3 +30,48 @@ class SendTestNotificationTestCase(BaseTestCase):
         self.assertEqual(email.to[0], "alice@example.org")
         self.assertTrue("X-Bounce-Url" in email.extra_headers)
         self.assertTrue("List-Unsubscribe" in email.extra_headers)
+
+    @patch("hc.api.transports.requests.request")
+    def test_it_handles_webhooks_with_no_down_url(self, mock_get):
+        mock_get.return_value.status_code = 200
+
+        self.channel.kind = "webhook"
+        self.channel.value = json.dumps(
+            {
+                "method_down": "GET",
+                "url_down": "",
+                "body_down": "",
+                "headers_down": {},
+                "method_up": "GET",
+                "url_up": "http://example-url",
+                "body_up": "",
+                "headers_up": {},
+            }
+        )
+        self.channel.save()
+
+        self.client.login(username="alice@example.org", password="password")
+        r = self.client.post(self.url, {}, follow=True)
+        self.assertRedirects(r, "/integrations/")
+        self.assertContains(r, "Test notification sent!")
+
+    def test_it_handles_webhooks_with_no_urls(self):
+        self.channel.kind = "webhook"
+        self.channel.value = json.dumps(
+            {
+                "method_down": "GET",
+                "url_down": "",
+                "body_down": "",
+                "headers_down": {},
+                "method_up": "GET",
+                "url_up": "",
+                "body_up": "",
+                "headers_up": {},
+            }
+        )
+        self.channel.save()
+
+        self.client.login(username="alice@example.org", password="password")
+        r = self.client.post(self.url, {}, follow=True)
+        self.assertRedirects(r, "/integrations/")
+        self.assertContains(r, "Could not send a test notification")
diff --git a/hc/front/views.py b/hc/front/views.py
index 03b036e7..3b314f39 100644
--- a/hc/front/views.py
+++ b/hc/front/views.py
@@ -747,6 +747,12 @@ def send_test_notification(request, code):
     dummy.last_ping = timezone.now() - td(days=1)
     dummy.n_pings = 42
 
+    if channel.kind == "webhook" and not channel.url_down:
+        if channel.url_up:
+            # If we don't have url_down, but do have have url_up then
+            # send "TEST is UP" notification instead:
+            dummy.status = "up"
+
     if channel.kind == "email":
         error = channel.transport.notify(dummy, channel.get_unsub_link())
     else: