Nette\Http\Session::start PHP Method

    public function start()
    {
        if (self::$started) {
            return;
        }
        $this->configure($this->options);
        $id = $this->request->getCookie(session_name());
        if (is_string($id) && preg_match('#^[0-9a-zA-Z,-]{22,256}\\z#i', $id)) {
            session_id($id);
        } else {
            unset($_COOKIE[session_name()]);
        }
        try {
            // session_start returns FALSE on failure only sometimes
            Nette\Utils\Callback::invokeSafe('session_start', [], function ($message) use(&$e) {
                $e = new Nette\InvalidStateException($message);
            });
        } catch (\Exception $e) {
        }
        if ($e) {
            @session_write_close();
            // this is needed
            throw $e;
        }
        self::$started = TRUE;
        /* structure:
        			__NF: Data, Meta, Time
        				DATA: section->variable = data
        				META: section->variable = Timestamp
        		*/
        $nf =& $_SESSION['__NF'];
        if (!is_array($nf)) {
            $nf = [];
        }
        // regenerate empty session
        if (empty($nf['Time'])) {
            $nf['Time'] = time();
            $this->regenerated = TRUE;
        }
        // resend cookie
        $this->sendCookie();
        // process meta metadata
        if (isset($nf['META'])) {
            $now = time();
            // expire section variables
            foreach ($nf['META'] as $section => $metadata) {
                if (is_array($metadata)) {
                    foreach ($metadata as $variable => $value) {
                        if (!empty($value['T']) && $now > $value['T']) {
                            if ($variable === '') {
                                // expire whole section
                                unset($nf['META'][$section], $nf['DATA'][$section]);
                                continue 2;
                            }
                            unset($nf['META'][$section][$variable], $nf['DATA'][$section][$variable]);
                        }
                    }
                }
            }
        }
        if ($this->regenerated) {
            $this->regenerated = FALSE;
            $this->regenerateId();
        }
        register_shutdown_function([$this, 'clean']);
    }

 protected function _before()
 {
     $this->session = new \Nette\Http\Session(new \Nette\Http\Request(new \Nette\Http\UrlScript()), new \Nette\Http\Response());
     $this->session = new \Kdyby\FakeSession\Session($this->session);
     $this->session->start();
     $this->wizard = new Wizard($this->session);
 }