EmailCommandTest.php

<?php

namespace Acme\DemoBundle\Tests\Command;

use Symfony\Component\Console\Tester\CommandTester;
use Symfony\Bundle\FrameworkBundle\Console\Application;
use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
use Acme\DemoBundle\Command\EmailCommand;

class EmailCommandTest extends WebTestCase
{
    public function testExecute()
    {
        $client = self::createClient();

        $application = new Application($client->getKernel());
        $application->add(new EmailCommand());

        $command = $application->find('demo:email');
        $commandTester = new CommandTester($command);
        $commandTester->execute(array('command' => $command->getName()));

        $this->assertRegExp('/Email sent/', $commandTester->getDisplay());

        $container = $client->getKernel()->getContainer();
        $profiler = $container->get('profiler');

        $mailerCollector = $profiler->get('swiftmailer');
        var_dump($mailerCollector->getMessages());

        $mailerLogger = $container->get('swiftmailer.plugin.messagelogger');
        var_dump($mailerLogger->getMessages());
    }
}