When a notification is timed out in the scheduled task that may happen because the notification has not been sent.

Which means the sent_at date for the notification could be empty causing the service callback to fail.

- Allow code to work if notification.sent_at or updated_at is None
- Update calls to send_delivery_status_to_service to send the data encrypted so that the task does not need to use the db.

tests/app/celery/test_scheduled_tasks.py

@@ -57,6 +57,7 @@ from app.models import (
     SMS_TYPE
 )
 from app.utils import get_london_midnight_in_utc
+from app.celery.service_callback_tasks import create_encrypted_callback_data
 from app.v2.errors import JobIncompleteError
 from tests.app.db import (
     create_notification, create_service, create_template, create_job, create_rate,
@@ -210,7 +211,7 @@ def test_should_not_update_status_of_letter_notifications(client, sample_letter_
 
 
 def test_timeout_notifications_sends_status_update_to_service(client, sample_template, mocker):
-    create_service_callback_api(service=sample_template.service)
+    callback_api = create_service_callback_api(service=sample_template.service)
     mocked = mocker.patch('app.celery.service_callback_tasks.send_delivery_status_to_service.apply_async')
     notification = create_notification(
         template=sample_template,
@@ -218,7 +219,9 @@ def test_timeout_notifications_sends_status_update_to_service(client, sample_tem
         created_at=datetime.utcnow() - timedelta(
             seconds=current_app.config.get('SENDING_NOTIFICATIONS_TIMEOUT_PERIOD') + 10))
     timeout_notifications()
-    mocked.assert_called_once_with([str(notification.id)], queue=QueueNames.CALLBACKS)
+
+    encrypted_data = create_encrypted_callback_data(notification, callback_api)
+    mocked.assert_called_once_with([str(notification.id), encrypted_data], queue=QueueNames.CALLBACKS)
 
 
 def test_should_update_scheduled_jobs_and_put_on_queue(notify_db, notify_db_session, mocker):