public function testCurl()
 {
     $client = new Client(array('client_id' => self::CLIENT_ID, 'client_secret' => self::CLIENT_SECRET, 'scope' => "user_read_write"));
     $client->setToken($this->expired_token);
     $options = array('secure' => false);
     $url = $client->get_api_url($options) . "/user";
     print_r($url);
     $headers = array("Content-Type" => "application/json", "Authorization" => "Bearer " . $this->expired_token);
     $curl_result = $client->do_request($url, false, $headers, "POST");
     $this->assertEquals($curl_result == false, true, 'Expect Curl result');
 }