Stack/CallableHttpKernel
HttpKernelInterface implementation based on callables.
It's mostly useful to test stack middlewares, and to mock the HttpKernelInterface on the fly.
Example
use Stack\CallableHttpKernel;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
$app = new CallableHttpKernel(function (Request $request) {
return new Response('Hello World!');
});