code: def test_app_delayed_config():
      app = Dash(server=False)
      app.init_app(app=Flask("test"), requests_pathname_prefix="/dash/")
  
      assert app.config.requests_pathname_prefix == "/dash/"
  
      with pytest.raises(AttributeError):
          app.config.name = "cannot update me"
  
imports: import os
  import logging
  import pytest
  from flask import Flask
  from dash import Dash, exceptions
  from dash._configs import pathname_configs, DASH_ENV_VARS, get_combined_config, load_dash_env_vars
  from dash._utils import AttributeDict
  from dash._get_paths import app_get_asset_url, app_get_relative_path, app_strip_relative_path, get_asset_url, get_relative_path, strip_relative_path
label_desc: Use image node_id 25 for calling a global function with example usage: test_app_delayed_config() without return types