code: def test_should_respond_403_not_readable(self, url_safe_serializer):
      dagbag = DagBag(dag_folder=EXAMPLE_DAG_FILE)
      dagbag.sync_to_db()
      dag: DAG = dagbag.dags[NOT_READABLE_DAG_ID]
  
      response = self.client.get(
          f"/api/v1/dagSources/{url_safe_serializer.dumps(dag.fileloc)}",
          headers={"Accept": "text/plain"},
          environ_overrides={"REMOTE_USER": "test"},
      )
      read_dag = self.client.get(
          f"/api/v1/dags/{NOT_READABLE_DAG_ID}",
          environ_overrides={"REMOTE_USER": "test"},
      )
      assert response.status_code == 403
      assert read_dag.status_code == 403
  
imports: from __future__ import annotations
  import ast
  import os
  from typing import TYPE_CHECKING
  import pytest
  from airflow.models import DagBag
  from airflow.security import permissions
  from tests.test_utils.api_connexion_utils import assert_401, create_user, delete_user
  from tests.test_utils.db import clear_db_dag_code, clear_db_dags, clear_db_serialized_dags
label_desc: Use image node_id 11 for calling the TestGetSource obj's underlying member method code with example usage: obj.test_should_respond_403_not_readable(url_safe_serializer) without return types