yii2-app-basic/tests/unit/_config.php

<?php

use yii\helpers\ArrayHelper;

$config = require(__DIR__ . '/../../config/web.php');

return ArrayHelper::merge($config, [
	'components' => [
		'fixture' => [
			'class' => 'yii\test\DbFixtureManager',
			'basePath' => '@tests/unit/fixtures',
		],
		'db' => [
			'dsn' => 'mysql:host=localhost;dbname=yii2_basic_unit',
		],
	],
]);