yii2-swiftmailer/tests/unit/framework/helpers/VarDumperTest.php

<?php
namespace yiiunit\framework\helpers;

use \yii\helpers\VarDumper;
use yii\test\TestCase;

class VarDumperTest extends TestCase
{
	public function testDumpObject()
	{
		$obj = new \StdClass();
		ob_start();
		VarDumper::dump($obj);
		$this->assertEquals("stdClass#1\n(\n)", ob_get_contents());
		ob_end_clean();
	}
}