Souke/vendor/yiisoft/yii2/test/DbFixture.php

<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\test;

use Yii;
use yii\db\Connection;
use yii\di\Instance;
use yii\base\Object;

/**
 * DbFixture is the base class for DB-related fixtures.
 *
 * DbFixture provides the [[db]] connection to be used by DB fixtures.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
abstract class DbFixture extends Fixture
{
    /**
     * @var Connection|array|string the DB connection object or the application component ID of the DB connection.
     * After the DbFixture object is created, if you want to change this property, you should only assign it
     * with a DB connection object.
     * Starting from version 2.0.2, this can also be a configuration array for creating the object.
     */
    public $db = 'db';


    /**
     * @inheritdoc
     */
    public function init()
    {
        parent::init();
        $this->db = Instance::ensure($this->db, Object::className());
    }
}