don't retry task if InvalidEmailError

just record it as a technical error - retrying wont fix a bad email

tests/app/celery/test_provider_tasks.py

@@ -1,10 +1,13 @@
 from celery.exceptions import MaxRetriesExceededError
+from notifications_utils.recipients import InvalidEmailError
+
+import app
 from app.celery import provider_tasks
 from app.celery.provider_tasks import send_sms_to_provider, send_email_to_provider, deliver_sms, deliver_email
 from app.clients.email import EmailClientException
 from app.models import Notification
+
 from tests.app.conftest import sample_notification
-import app
 
 
 def test_should_have_decorated_tasks_functions():
@@ -229,3 +232,12 @@ def test_should_go_into_technical_error_if_exceeds_retries_on_deliver_email_task
 
     db_notification = Notification.query.filter_by(id=notification.id).one()
     assert db_notification.status == 'technical-failure'
+
+def test_should_technical_error_and_not_retry_if_invalid_email(sample_notification, mocker):
+    mocker.patch('app.delivery.send_to_providers.send_email_to_provider', side_effect=InvalidEmailError('bad email'))
+    mocker.patch('app.celery.provider_tasks.deliver_email.retry')
+
+    deliver_email(sample_notification.id)
+
+    assert provider_tasks.deliver_email.retry.called is False
+    assert sample_notification.status == 'technical-failure'