Please write audio tests (was: Playing ULAW sample correctly?)

[Nicklas Börjesson]

>Or use a goertzel detector for the transmitted tone(s).
>It is also quite simple to generate sine waves without any trig.

Just another, less advanced, idea,

Even easier would making a really slow square wave(~0.5 Hz) that follows a simple pattern, like 80, 80, 80, -80, -80, -80, 80, 80, 80...for 5 seconds.
Then one would easily be able to find the signal in the data without any advanced tricks. 
Just (signal<0) or not for a specified period would suffice as detection.
Maybe stutter and sound quality would not be tested, however it would be a simple first step.

BTW, wouldn't stutter affect a straight line as much as it would a sound wave?
If you know that the wave isn't a wave but is supposed to follow a straight line, wouldn't then all deviations be stutter?
The soundsystem doesn't treat a stream of similar bytes any different from a sine wave, does it?

Of course, this will obviously not work through a microphone, but I can't see how that loop would be relevant to test. Being hardware and all.

//Nicklas