Symfony2 functional testing using Doctrine, sharing connections between requests

config_test_functional.yml

#app/config/config_test_functional.yml

imports:
    - { resource: config_test.yml }

SharedDoctrineConnectionsClient

namespace BenMichalski\AppBundle\Test\Client;

/**
 * Heavily inspired by http://alexandre-salome.fr/blog/Symfony2-Isolation-Of-Tests
 */
class SharedDoctrineConnectionsClient extends BaseClient
{
    /**
     * @var array
     */
    protected $connectionsByServiceId;

    /**
     * @var bool
     */
    protected $hasPerformedRequest = false;

    /**
     * {@inheritdoc}
     */
    protected function doRequest($request)
    {
        if ($this->hasPerformedRequest) {
            $this->kernel->shutdown();
            $this->kernel->boot();
        }

        $this->handleConnections();

        $this->hasPerformedRequest = true;

        return $this->kernel->handle($request);
    }

    /**
     * Saves connections to be shared if needed,
     * else injects them into the container so that are shared between requests.
     */
    protected function handleConnections()
    {
        $container = $this->getContainer();

        if (null === $this->connectionsByServiceId) {
            $connectionServices = $container->getParameter('doctrine.connections');

            $this->connectionsByServiceId = [];

            foreach ($connectionServices as $serviceId) {
                $this->connectionsByServiceId[$serviceId] = $container->get($serviceId);
            }
        } else {
            foreach ($this->connectionsByServiceId as $serviceId => $service) {
                $container->set($serviceId, $service);
            }
        }
    }
}

SharedDoctrineConnectionsClientAppExtension

namespace BenMichalski\AppBundle\DependencyInjection;

use Symfony\Component\Config\FileLocator;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Loader;
use Symfony\Component\HttpKernel\DependencyInjection\Extension;
use BenMichalski\AppBundle\Test\Client\SharedDoctrineConnectionsClient;

class AppExtension extends Extension
{
    /**
     * {@inheritDoc}
     */
    public function load(
        array $configs,
        ContainerBuilder $container
    ) {
        $configuration = new Configuration();
        $config = $this->processConfiguration(
            $configuration,
            $configs
        );

        $loader = new Loader\YamlFileLoader(
            $container,
            new FileLocator(
                __DIR__
                . '/../Resources/config'
            )
        );

        $loader->load('services.yml');

        if ('test_functional' === $container->getParameter('kernel.environment')) {
            $container->setParameter('test.client.class', SharedDoctrineConnectionsClient::class);
        }
    }
}

SharedDoctrineConnectionsClientTestCase

use Symfony\Bundle\FrameworkBundle\Test\WebTestCase;

class MyTest extends WebTestCase
{
    /**
    * {@inheritdoc}
    */
    protected static function createClient(array $options = [], array $server = [])
    {
        $options['environment'] = 'test_functional';
    
        return parent::createClient($options, $server);
    }
}