Slim/Pimple bridge concept

Bridge.php

<?php

// See http://pimple.sensiolabs.org/#extending-a-container

final class Bridge implements ServiceProviderInterface
{
    public function __construct(PimpleContainer $container)
    {
        $this->container = $container;
    }

    public function register(PimpleContainer $pimple)
    {
        foreach ($this->container->keys() as $key) {
            $pimple[$key] = $this->container->raw($key);
        }
    }
}

BridgeContainer.php

<?php

final class BridgeContainer extends PimpleContainer implements ContainerInterface
{
    /********************************************************************************
     * Methods to satisfy Interop\Container\ContainerInterface
     *******************************************************************************/

    /**
     * Finds an entry of the container by its identifier and returns it.
     *
     * @param string $id Identifier of the entry to look for.
     *
     * @throws ContainerValueNotFoundException No entry was found for this identifier.
     * @throws ContainerException              Error while retrieving the entry.
     *
     * @return mixed Entry.
     */
    public function get($id)
    {
        if (!$this->offsetExists($id)) {
            throw new ContainerValueNotFoundException(sprintf('Identifier "%s" is not defined.', $id));
        }

        return $this->offsetGet($id);
    }

    /**
     * Returns true if the container can return an entry for the given identifier.
     * Returns false otherwise.
     *
     * @param string $id Identifier of the entry to look for.
     *
     * @return bool
     */
    public function has($id)
    {
        return $this->offsetExists($id);
    }
}

BridgeTest.php

<?php

namespace Bridge\Test;

use Bridge\Bridge;
use Bridge\BridgeContainer;
use Slim\Container as SlimContainer;
use Pimple\Container as PimpleContainer;

class BridgeTest extends \PHPUnit_Framework_TestCase
{
    public function testProvider()
    {
        $pimpleContainer = new PimpleContainer();
        $pimpleContainer['test'] = function ($c) {
            return 'TEST';
        };
        $bridge = new Bridge($pimpleContainer);

        $slimContainer = new SlimContainer();
        $slimContainer->register($bridge);

        $this->assertEquals('TEST', $slimContainer->get('test'));
    }

    public function testCustomContainer()
    {
        $slimContainer = new SlimContainer();

        // Honors Pimple\ServiceProviderInterface
        $bridge = new Bridge($slimContainer);

        $myContainer = new BridgeContainer();
        $myContainer['test'] = function ($c) {
            return 'TEST';
        };
        $myContainer->register($bridge);

        $this->assertEquals($slimContainer->get('errorHandler'), $myContainer->get('errorHandler'));
        $this->assertInstanceOf('Slim\Handlers\Error', $myContainer->get('errorHandler'));
        $this->assertEquals('TEST', $myContainer->get('test'));
    }
}