PHP Websocket test authentication

I am trying to test a scenario, that on the one hand, anonymous users should immediately get a disconnect from a Websocket connection and on the other hand, authenticated users should stay in the websocket connection. The first case is easy testable by using the code down under. The authentication process is not working.

For session storage, I am using Cookie authentication in combination with a database: Symfony PDO Session Storage. It's all working fine, but when it comes to testing the described behaviour by using authentication, I don't know how to authenticate the user in a test. As a client, I am using Pawl asynchronous Websocket client. This looks the following:

\Ratchet\Client\connect('ws://127.0.0.1:8080')->then(function($conn) {
    $conn->on('message', function($msg) use ($conn) {
        echo "Received: {$msg}\n";
    });

    $conn->send('Hello World!');
}, function ($e) {
    echo "Could not connect: {$e->getMessage()}\n";
});

I know that as a third parameter, I can pass header information to the "connect" method, but I cannot find a way so that the client is connected and the cookie is passed correctly during the ws handshake. I thought of something like:

1. Authenticate a client by creating an authentication token
2. I create a new entry in the session table in database with serialized user
3. I pass the created cookie as a third argument to the connect method

This is the theory I thought that would work, but the user always stays anonym on websocket side.

For server side websocket implementation, I am using Ratchet, which is being wrapped by the following Symfony bundle: Gos Websocket Bundle

How to authenticate the user when testing websockets?