code: def test_app_state_connection_error(_):
      """Test an error message when a connection to retrieve the state can't be established."""
      app_state = AppState(port=8000)
      with pytest.raises(
          AttributeError,
          match=r"Failed to connect and fetch the app state\. Is the app running?",
      ):
          app_state._request_state()
  
      with pytest.raises(
          AttributeError,
          match=r"Failed to connect and fetch the app state\. Is the app running?",
      ):
          app_state.var = 1
  
imports: import os
  from re import escape
  from unittest import mock
  import lightning.app
  import pytest
  import requests
  from lightning.app import LightningApp, LightningFlow, LightningWork
  from lightning.app.structures import Dict, List
  from lightning.app.utilities.app_helpers import AppStatePlugin, BaseStatePlugin
  from lightning.app.utilities.state import AppState
  from lightning_cloud.openapi import Externalv1LightningappInstance, V1LightningappInstanceStatus
label_desc: Use image node_id 8 for calling a global function with example usage: test_app_state_connection_error(_) without return types