yii2-app-basic/tests/codeception/config/functional.php

<?php
$_SERVER['SCRIPT_FILENAME'] = YII_TEST_ENTRY_FILE;
$_SERVER['SCRIPT_NAME'] = YII_TEST_ENTRY_URL;

/**
 * Application configuration for functional tests
 */
return yii\helpers\ArrayHelper::merge(
    require(__DIR__ . '/../../../config/web.php'),
    require(__DIR__ . '/config.php'),
    [

    ]
);