code: def test_pathname_prefix_from_environ_app_name(empty_environ):
      os.environ["DASH_APP_NAME"] = "my-dash-app"
      _, routes, req = pathname_configs()
      assert req == "/my-dash-app/"
      assert routes == "/"
  
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 4 for calling a global function with example usage: test_pathname_prefix_from_environ_app_name(empty_environ) without return types