I don't much test my own systems, but I do a lot of fixing things, refoams, etc, and I like this track for bass testing:
Mainly because not only is it low, I can hear any cabinet rattles, voice coil rattles/scrapes, etc., but it also has some simultaneous high-notes, so you can hear any crossover issues. Basically if I play this track and it sounds clean at high volume, it passes one of my quality control checks.
If I'm testing speakers that can't go that low, I like to use AC/DC Back in Black. It's very crisp and punchy, and great for showing off speakers that have a narrow frequency response.