class SomeRequestService
{
    private $assert;
    private $request;

    public function __construct(Request $request, AssertInterface $assert)
    {
        $this->request = $request;
        $this->assert = $assert;
    }

    public function someMethod()
    {
        $session = $this->request;

        $this->assert->true($session->has('some_attribute'), 'The session should have a "some_attribute"', $session());
        $this->assert->same('test', $session->get('some_attribute'), 'The session attribute "some_attribute" should be "test" but got %s', $this->request);
        // or
        $this->assert->regex('/^test/', $session->get('some_attribute'), 'The session attribute "some_attribute" should start with "test" but got %s', $this->request);
        // or even better
        $this->assert->uuid($session->get('some_uuid'), 'The session attribute "some_uuid" is invalid" got %s', $this->request);

// from anywhere using SomeService instance
$assert->stopwatch('some_service_event', '<', 1000, $someService);