Add default billing entity from origin

ref #198

src/tests/test_api_exoscale.py

@@ -99,6 +99,36 @@ def test_successful_onboarding_new_organization(
     assert "redis/offering/" in welcome_email.body
 
 
+@pytest.mark.django_db
+def test_new_organization_inherits_origin(
+    osb_client,
+    test_service,
+    test_service_offering,
+    valid_osb_payload,
+    exoscale_origin,
+    instance_id,
+    billing_entity,
+):
+    valid_osb_payload["service_id"] = test_service.osb_service_id
+    valid_osb_payload["plan_id"] = test_service_offering.osb_plan_id
+    exoscale_origin.billing_entity = billing_entity
+    exoscale_origin.save()
+
+    response = osb_client.put(
+        f"/api/osb/v2/service_instances/{instance_id}",
+        data=json.dumps(valid_osb_payload),
+        content_type="application/json",
+    )
+
+    assert response.status_code == 201
+    response_data = json.loads(response.content)
+    assert response_data["message"] == "Successfully enabled service"
+
+    org = Organization.objects.get(osb_guid="test-org-guid-123")
+    assert org.name == "Test Organization Display"
+    assert org.billing_entity == exoscale_origin.billing_entity
+
+
 @pytest.mark.django_db
 def test_duplicate_organization_returns_existing(
     osb_client,