Set postage for templated letters when the address is not from the united-kingdom.

If the address is from the united-kingdom use the postage from the template.

tests/app/v2/notifications/test_post_letter_notifications.py

@@ -174,6 +174,30 @@ def test_post_letter_notification_stores_country(
         'Kronprinzenpalais\n'
         'Germany'
     )
+    assert notification.postage == 'europe'
+
+
+def test_post_letter_notification_international_sets_rest_of_world(
+        client, notify_db_session, mocker
+    ):
+        service = create_service(service_permissions=[LETTER_TYPE, INTERNATIONAL_LETTERS])
+        template = create_template(service, template_type="letter")
+        mocker.patch('app.celery.tasks.letters_pdf_tasks.get_pdf_for_templated_letter.apply_async')
+        data = {
+            'template_id': str(template.id),
+            'personalisation': {
+                'address_line_1': 'Prince Harry',
+                'address_line_2': 'Toronto',
+                'address_line_5': 'Canada',
+            }
+        }
+
+        resp_json = letter_request(client, data, service_id=service.id)
+
+        assert validate(resp_json, post_letter_response) == resp_json
+        notification = Notification.query.one()
+
+        assert notification.postage == 'rest-of-world'
 
 
 @pytest.mark.parametrize('permissions, personalisation, expected_error', (