Update create_custom_template test helper to create history object

`create_custom_template` is not using `dao_create_template` since
it explicitly sets a template id. Notifications.template relationship
now refers to a TemplateHistory objects, so we need to make sure that
`create_custom_template` creates a matching TemplateHistory record
when it creates a Template.

tests/app/celery/test_scheduled_tasks.py

@@ -48,7 +48,6 @@ from app.models import (
     NotificationHistory,
     Service,
     StatsTemplateUsageByMonth,
-    Template,
     JOB_STATUS_READY_TO_SEND,
     JOB_STATUS_IN_PROGRESS,
     JOB_STATUS_SENT_TO_DVLA,
@@ -81,14 +80,13 @@ def _create_slow_delivery_notification(provider='mmg'):
         service = create_service(
             service_id=current_app.config.get('FUNCTIONAL_TEST_PROVIDER_SERVICE_ID')
         )
-    template = Template.query.get(current_app.config['FUNCTIONAL_TEST_PROVIDER_SMS_TEMPLATE_ID'])
-    if not template:
-        template = create_custom_template(
-            service=service,
-            user=service.users[0],
-            template_config_name='FUNCTIONAL_TEST_PROVIDER_SMS_TEMPLATE_ID',
-            template_type='sms'
-        )
+
+    template = create_custom_template(
+        service=service,
+        user=service.users[0],
+        template_config_name='FUNCTIONAL_TEST_PROVIDER_SMS_TEMPLATE_ID',
+        template_type='sms'
+    )
 
     create_notification(
         template=template,

tests/app/conftest.py

@@ -14,6 +14,7 @@ from app import db
 from app.models import (
     Service,
     Template,
+    TemplateHistory,
     ApiKey,
     Job,
     Notification,
@@ -38,6 +39,7 @@ from app.dao.notifications_dao import dao_create_notification
 from app.dao.invited_user_dao import save_invited_user
 from app.dao.provider_rates_dao import create_provider_rates
 from app.clients.sms.firetext import FiretextClient
+from app.history_meta import create_history
 from tests import create_authorization_header
 from tests.app.db import (
     create_user,
@@ -974,6 +976,7 @@ def create_custom_template(service, user, template_config_name, template_type, c
         }
         template = Template(**data)
         db.session.add(template)
+        db.session.add(create_history(template, TemplateHistory))
         db.session.commit()
     return template