public void ContextToAudio()
 {
     var yc = new YoutubeContext(Url) {BaseDirectory = new DirectoryInfo(Path.GetTempPath())};
     try {
         yc.ToAudio();
         Assert.IsTrue(File.Exists(yc.AudioPath.FullName));
         Debug.WriteLine(yc.AudioPath.FullName);
     } finally {
         if (yc.AudioPath !=null && File.Exists(yc.AudioPath.FullName))
             File.Delete(yc.AudioPath.FullName);
         Assert.IsFalse(File.Exists(yc.AudioPath.FullName));
     }
 }