Car died while driving

I'm just gonna do the short version. Driving home from work, stereo started skipping halfway home, made it to offramp stereo died, car still running though. Drove down the road a bit more, the ac died afterwards, then the dash board died along with the speedometer, then finally my car died itself but i had the momentum to park it somewhere thank god.

Anyhow i tested the battery and alternator at O'Reilly's and both were fine so i dont know what else would cause this to happen to me.