public function testStartRecordingWithParameters()
 {
     $tropo = new Tropo();
     $tropo->StartRecording('recording', 'audio/mp3', 'POST', 'password', 'http://blah.com/recordings/1234.wav', 'jose');
     $this->assertEquals('{"tropo":[{"recording":{"format":"audio/mp3","method":"POST","password":"******","url":"http://blah.com/recordings/1234.wav","username":"******"}}]}', sprintf($tropo));
 }