Add test for updating default branding

tests/app/organisation/test_rest.py

@@ -4,7 +4,14 @@ import pytest
 
 from app.models import Organisation
 from app.dao.organisation_dao import dao_add_service_to_organisation, dao_add_user_to_organisation
-from tests.app.db import create_domain, create_organisation, create_service, create_user
+from tests.app.db import (
+    create_domain,
+    create_email_branding,
+    create_letter_branding,
+    create_organisation,
+    create_service,
+    create_user,
+)
 
 
 def test_get_all_organisations(admin_request, notify_db_session):
@@ -224,6 +231,33 @@ def test_update_other_organisation_attributes_doesnt_clear_domains(
     ]
 
 
+def test_update_organisation_default_branding(
+    admin_request,
+    notify_db_session,
+):
+
+    org = create_organisation(name='Test Organisation')
+
+    email_branding = create_email_branding()
+    letter_branding = create_letter_branding()
+
+    assert org.email_branding is None
+    assert org.letter_branding is None
+
+    admin_request.post(
+        'organisation.update_organisation',
+        _data={
+            'email_branding_id': str(email_branding.id),
+            'letter_branding_id': str(letter_branding.id),
+        },
+        organisation_id=org.id,
+        _expected_status=204
+    )
+
+    assert org.email_branding == email_branding
+    assert org.letter_branding == letter_branding
+
+
 def test_post_update_organisation_raises_400_on_existing_org_name(
         admin_request, sample_organisation):
     org = create_organisation()