Make notifications_api_service_identifier required on NotificationCon…

…figurationModel

docs/setup_config.rst

@@ -50,9 +50,9 @@ Example file:
                 - Foo
                 - Bar
 
-If the ``notifications_api_service_identifier`` is specified, it might also be useful
+Because ``notifications_api_service_identifier`` is required, it might also be useful
 to use the `ServiceConfigurationStep <https://zgw-consumers.readthedocs.io/en/latest/setup_config.html>`_
-from ``zgw-consumers``.
+from ``zgw-consumers`` to configure the ``Service`` object for the notifications API.
 
 Note that the ``uuid`` field in your subscriptions config must point to an existing
 ``Abonnement`` in the Open Notificaties service configured through ``notifications_config``.

notifications_api_common/contrib/setup_configuration/models.py

@@ -6,7 +6,8 @@
 
 class NotificationConfigurationModel(ConfigurationModel):
     notifications_api_service_identifier: str = DjangoModelRef(
-        NotificationsConfig, "notifications_api_service", default=""
+        NotificationsConfig,
+        "notifications_api_service",
     )
 
     class Meta:

tests/test_configuration_steps.py

@@ -1,4 +1,5 @@
 import pytest
+from django_setup_configuration.exceptions import PrerequisiteFailed
 from django_setup_configuration.test_utils import execute_single_step
 from zgw_consumers.test.factories import ServiceFactory
 
@@ -57,17 +58,16 @@ def test_execute_configuration_step_update_existing():
 
 @pytest.mark.django_db
 def test_execute_configuration_step_without_service_success():
-    execute_single_step(
-        NotificationConfigurationStep, yaml_source=CONFIG_FILE_PATH_NO_SERVICE
+    with pytest.raises(PrerequisiteFailed) as excinfo:
+        execute_single_step(
+            NotificationConfigurationStep, yaml_source=CONFIG_FILE_PATH_NO_SERVICE
+        )
+
+    assert (
+        "notifications_config.notifications_api_service_identifier\n  Input should be a valid string"
+        in str(excinfo.value)
     )
 
-    config = NotificationsConfig.get_solo()
-
-    assert config.notifications_api_service is None
-    assert config.notification_delivery_max_retries == 1
-    assert config.notification_delivery_retry_backoff == 2
-    assert config.notification_delivery_retry_backoff_max == 3
-
 
 @pytest.mark.django_db
 def test_execute_configuration_step_idempotent():