code: def test_post_should_respond_400_for_invalid_payload(
      self, payload, error_message
  ):
      response = self.client.post(
          "/auth/fab/v1/roles",
          json=payload,
          environ_overrides={"REMOTE_USER": "test"},
      )
      assert response.status_code == 400
      assert response.json == {
          "detail": error_message,
          "status": 400,
          "title": "Bad Request",
          "type": EXCEPTIONS_LINK_MAP[400],
      }
  
imports: from __future__ import annotations
  import pytest
  from airflow.api_connexion.exceptions import EXCEPTIONS_LINK_MAP
  from airflow.providers.fab.auth_manager.models import Role
  from airflow.providers.fab.auth_manager.security_manager.override import EXISTING_ROLES
  from airflow.security import permissions
  from tests.test_utils.api_connexion_utils import assert_401, create_role, create_user, delete_role, delete_user
label_desc: Use image node_id 2 for calling the TestPostRole obj's underlying member method code with example usage: obj.test_post_should_respond_400_for_invalid_payload(payload, error_message) without return types