config_test.yml

doctrine:
    dbal:
        driver:   pdo_sqlite
        memory:   true

ImplementationTest.php

<?php

class ImplementationTest extends TestCase
{
    public function setUp()
    {
        parent::setUp();
        $this->setUpDb();
    }

    public function testCreateReturnsNewUserWithValidParams()
    {
        $client = static::createClient();

        // GET /foo - queries table from database for a list
        $crawler = $client->request('GET', '/foo');
    }
}

TestCase.php

<?php

use Symfony\Bundle\FrameworkBundle\Console\Application;
use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;
use Symfony\Component\Console\Input\StringInput;
use Symfony\Component\DependencyInjection\Container;

class TestCase extends WebTestCase
{
    /**
     * @var Container
     */
    protected $container;

    /**
     * @var Application
     */
    protected $console;

    public function setUp()
    {
        static::bootKernel();

        $this->container = static::$kernel->getContainer();
        $this->console = new Application(static::$kernel);
        $this->console->setAutoExit(false);
    }

    protected function runCommand($command)
    {
        $command = sprintf('%s --quiet', $command);

        $this->console->run(
            new StringInput($command)
        );
    }

    protected function setUpDb()
    {
        $this->runCommand('doctrine:database:create --env=test');
        $this->runCommand('doctrine:schema:update --env=test --force');
    }
}