Normally, all Postscript printers have a built-in self test, but I don't
know how to work it on any of the apple products.
I believe that it can be interfaced to a PC, but may be slow.
Toner should be available, it was a Canon-engine printer, I think the "CX"
engine, same as the original HP Laserjet. It MIGHT be an "SX" engine, which
would be much better. In either case, you should be able to get toner,
although it won't be "on the shelves" at a local retail store.