text: from unittest import TestCase
  
  from aiortc.mediastreams import AudioStreamTrack, VideoStreamTrack
  
  
  class MediaStreamTrackTest(TestCase):
      def test_audio(self):
          track = AudioStreamTrack()
          self.assertEqual(track.kind, "audio")
          self.assertEqual(len(track.id), 36)
  
      def test_video(self):
          track = VideoStreamTrack()
          self.assertEqual(track.kind, "video")
          self.assertEqual(len(track.id), 36)
  