SimpleSAML\Test\BuiltInServer::start PHP Method

    public function start()
    {
        $port = mt_rand(1025, 65535);
        $this->address = 'localhost:' . $port;
        $command = sprintf('php -S %s -t %s %s >> /dev/null 2>&1 & echo $!', $this->address, $this->docroot, $this->router);
        // execute the command and store the process ID
        $output = array();
        exec($command, $output);
        $this->pid = (int) $output[0];
        // wait until it's listening for connections to avoid race conditions
        $start = microtime(true);
        while (($sock = @fsockopen('localhost', $port, $errno, $errstr, 10)) === false) {
            // set a 5 secs timeout waiting for the server to start
            if (microtime(true) > $start + 5) {
                $this->pid = false;
                // signal failure
                $this->address = false;
                break;
            }
        }
        if ($sock !== false) {
            fclose($sock);
        }
        return $this->address;
    }

 /**
  * The setup method that is run before any tests in this class.
  */
 protected function setup()
 {
     $this->server = new BuiltInServer('configLoader');
     $this->server_addr = $this->server->start();
     $this->server_pid = $this->server->getPid();
     $this->shared_file = sys_get_temp_dir() . '/' . $this->server_pid . '.lock';
     @unlink($this->shared_file);
     // remove it if it exists
 }