code: def test_valid_pathname_prefix_init(
      empty_environ,
      route_prefix,
      req_prefix,
      expected_route,
      expected_req,
  ):
      _, routes, req = pathname_configs(
          routes_pathname_prefix=route_prefix,
          requests_pathname_prefix=req_prefix,
      )
  
      if expected_route is not None:
          assert routes == expected_route
      assert req == expected_req
  
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 2 for calling a global function with example usage: test_valid_pathname_prefix_init(empty_environ, route_prefix, req_prefix, expected_route, expected_req) without return types