I watched an interview with Magic. He liked the "high end" ladies, the streetwalkers, ladies at the club ... basically anything with 2 tits, a hole, and a heartbeat. There's no way of knowing who he got HIV from.
As for STD testing in the hobby, its basically useless as a tool for prevention. Unless your partner has been abstinent for at least 6 months prior to the test, and with nobody else since, then that test was obsolete the moment it was taken. That basically includes everyone around here.
Now, I'm not advocating you shouldn't get tested. I go twice a year for my check-ups. However, its a matter of my own personal health and safety.