Could not initialize class net.sf.cglib.proxy.Enhancer

<?php

namespace Facebook\WebDriver;
use Facebook\WebDriver\Remote\DesiredCapabilities;
use Facebook\WebDriver\Remote\RemoteWebDriver;
use PHPUnit\Framework\TestCase;

use function PHPUnit\Framework\assertStringContainsString;

require_once('vendor/autoload.php');

class loginTest extends TestCase {

    public function testAcessarTelaDeLogin (){

        $host = 'http://localhost:4444/wd/hub';
        $capabilities = DesiredCapabilities::chrome();
        $driver = RemoteWebDriver::create($host, $capabilities);

        $url = 'https://github.com/login';

        $driver->navigate()->to($url);

        self::assertStringContainsString('Sign in to GitHub', $driver->getPageSource());

    }
}

Quando eu rodo o teste aprensenta esse erro no console

cannot open file "loginTest.php".
[ffigueiredo@fedora php-test]$ php vendor/bin/phpunit tests/
PHP Fatal error:  Uncaught Facebook\WebDriver\Exception\UnknownServerException:
Could not initialize class net.sf.cglib.proxy.Enhancer in /home/ffigueiredo/Documentos/douglas-projetos/php-test/vendor/php-webdriver/webdriver/lib/Exception/WebDriverException.php:114