#[cfg(test)]
mod tests {
    use rodio::{source::SineWave, OutputStream, Sink, Source};
    use std::time::Duration;

    #[test]
    fn skip_one_test() {
        let (_stream, stream_handle) = OutputStream::try_default().unwrap();
        let sink = Sink::try_new(&stream_handle).unwrap();
        let source = SineWave::new(440.0)
            .take_duration(Duration::from_secs_f32(5.))
            .amplify(0.20);
        let source2 = SineWave::new(440.0)
            .take_duration(Duration::from_secs_f32(5.))
            .amplify(0.20);

        sink.append(source);
        sink.append(source2);

        assert_eq!(sink.len(), 2); // OK as expected

        sink.skip_one();

        assert_eq!(sink.len(), 1); // shouln't this be true? I am getting sink.len() == 2 instead
    }
}