protected function tearDown() {
$this->kernel = null;
$this->cache = null;
$this->caches = null;
$this->request = null;
$this->response = null;
$this->responses = null;
$this->cacheConfig = null;
$this->catch = null;
$this->esi = null;
$this
->clearDirectory(sys_get_temp_dir() . '/http_cache');
}