I had found two errors

PHP 7.3.1 (windows cli)

websockets.php:
protected function connect($socket) {
    $user = new $this->userClass(uniqid('u'), $socket, 1); // I had to add the third argument else E_FATAL

testwebsock.php
$echo = new echoServer("0.0.0.0","9000",2048); // Also 3rd argument missing else E_FATAL

Your server and client works very well. Nice work!

