av1_videos = {
        p
        for p in glob.glob("**/*.mp4", recursive=True)
        if is_av1_video(p)
    }

    assert av1_videos == set()

    assert not any(is_av1_video(p) for p in glob.glob("**/*.mp4", recursive=True))

    assert all(not is_av1_video(p) for p in glob.glob("**/*.mp4", recursive=True))

> A more direct way that also bails out early

If it bails out early it is of no use to them.

> This means that if the test fails, I can see all the affected videos at once. If the test failed on the first AV1 video, I’d only know about one video at a time, which would slow me down.