How to get Symfony2 services in functional test

SomeClassTest.php

    /**
     * @var \Doctrine\ORM\EntityManager
     */
    private $em;

    public function setUp()
    {
        static::$kernel = static::createKernel();
        static::$kernel->boot();
        $this->em = static::$kernel->getContainer()
            ->get('doctrine')
            ->getManager();
    }