Newbie Q on post repair testing of Amp

In the very near future, I plan to finally get around to replacing a speaker relay and memory battery in my late '80s receiver.

My question is how I can test it before hooking it up to my good (and only) speakers.

Do I need to get dummy loads?
Buy cheap speakers?
Or just plug it in with no load on speaker outputs and try it, by waiting for relay click?