Extension of Codeception\Module\Yii2 to support multiple DB Connections and Shared Transactions.

Extended Codeception Yii2 Module

<?php
namespace tests\codeception\common\Module;

use Codeception\Lib\Interfaces\ActiveRecord;

/**
 * Extended Codeception Yii2 Module:
 * 
 * This module provides integration with [Yii framework](http://www.yiiframework.com/) (2.0).
 * This custom module extends the original Codeception\Module\Yii2 class to support Multiple DBs and Shared Transactions.
 * It will construct a custom Yii2 Client object and set DB objects onto Client to set onto new Applications per Request.
 * The purpose of this is to share DB Connections with an open Transaction across multiple Requests within one test function.
 * Functional Tests can call multiple Requests, each creating DB records, and all will be rolled back at the end of a test.
 * 
 * ## Config
 *
 * Must set your functional.suite.yml configuration file as shown below.
 * - Note that 'Yii2' was removed under 'modules', and the path to this module was included.
 * - Also note that 'config' was updated for the new module path, and cleanup: true was added.
 *
 * * configFile *required* - the path to the application config file
 * * cleanup *optional* - boolean to enable DB Transactions on Functional Tests
 *
 * The entry script must return the application configuration array.
 *
 * You can use this module by setting params in your functional.suite.yml:
 * <pre>
 * class_name: FunctionalTester
 * modules:
 *     enabled:
 *         - tests\codeception\common\Module\Yii2
 *         - TestHelper
 *     config:
 *         tests\codeception\common\Module\Yii2:
 *             configFile: '/path/to/config.php'
 *             cleanup: true
 * </pre>
 */
class Yii2 extends \Codeception\Module\Yii2 implements ActiveRecord
{
    /**
     * Array of DB Connection objects indexed by App DB component id string.
     * 
     * @var Array[string => \yii\db\Connection] 
     */
    protected $dbs = array();
    
    /**
     * Array of DB Transaction objects indexed by App DB component id string.
     * 
     * @var Array[string => \yii\db\Transaction] 
     */
    protected $transactions = array();
    
    public function _before(\Codeception\TestCase $test)
    {
        $this->client = new \tests\codeception\common\Lib\Connector\Yii2();
        $this->client->configFile = \Codeception\Configuration::projectDir().$this->config['configFile'];
        $this->app = $this->client->startApp();

        if ($this->config['cleanup'] && isset($this->app->db)) {
            $this->dbs = $this->_getDbConnections($this->app);
            foreach($this->dbs as $db_id => $db) {
                $this->transactions[$db_id] = $db->beginTransaction();
            }
            $this->client->dbs = $this->dbs;
        }
    }

    public function _after(\Codeception\TestCase $test)
    {
        if($this->config['cleanup']) {
            $this->config['cleanup'] = false;
            parent::_after($test);
            if(sizeof($this->transactions) > 0) {
                foreach($this->transactions as $db_id => $transaction) {
                    $transaction->rollback();
                }
            }
            $this->config['cleanup'] = true;
        }
        else {
            parent::_after($test);
        }
    }

    protected function _getDbConnections($app)
    {
        $dbs = array();
        $components = $app->getComponents();
        foreach($components as $id => $component) {
            if(is_a($component, 'yii\db\Connection')) {
                $dbs[$id] = $component;
            }
            else if(is_array($component) && isset($component['dsn'])) {
                $component = $app->$id;
                if(is_a($component, 'yii\db\Connection')) {
                    $dbs[$id] = $component;
                }
            }
        }
        return $dbs;
    }
}