def f() =
  s =
    input.external.rawaudio(
      channels=1,
      samplerate=44100,
      restart=true,
      "ffmpeg -re -f lavfi -i sine=frequency=1000:duration=60 -f s16le -acodec \
       pcm_s16le -ar 44100 -"
    )

  s =
    ffmpeg.encode.audio(%ffmpeg(%audio(codec = "libmp3lame", channels = 1)), s)

  s = source.on_track(s, fun (_) -> test.pass())
  output.dummy(fallible=true, s)
end

test.check(f)
