public function testSetEror()
 {
     $client = new Client(array('client_id' => self::CLIENT_ID, 'client_secret' => self::CLIENT_SECRET, 'scope' => "user_read_write"));
     $err_msg = "Test Error Message";
     $client->setError($err_msg);
     $this->assertEquals($client->getError(), $err_msg, 'Expect Error Message');
 }