Notification error log handler (#403)

* Add a notifications debug/error log interface (Link available under the notification URLs list)

changedetectionio/tests/test_notification.py

@@ -226,3 +226,32 @@ def test_check_notification(client, live_server):
     )
     assert b"Notification Body and Title is required when a Notification URL is used" in res.data
 
+
+    # Check we capture the failure, we can just use trigger_check = y here
+    res = client.post(
+        url_for("edit_page", uuid="first"),
+        data={"notification_urls": "jsons://broken-url.changedetection.io/test",
+              "notification_title": "xxx",
+              "notification_body": "xxxxx",
+              "notification_format": "Text",
+              "url": test_url,
+              "tag": "my tag",
+              "title": "my title",
+              "headers": "",
+              "fetch_backend": "html_requests",
+              "trigger_check": "y"},
+        follow_redirects=True
+    )
+
+    time.sleep(3)
+
+    # The error should show in the notification logs
+    res = client.get(
+        url_for("notification_logs"))
+    assert bytes("Name or service not known".encode('utf-8')) in res.data
+
+    # And it should be listed on the watch overview
+    res = client.get(
+        url_for("index"))
+    assert bytes("Notification error detected".encode('utf-8')) in res.data
+