Just the one discharge at max energy? That's a test for wimps, Phil! LOL
And (just out of interest)... are you able to cite any manufacturer or "official body" who has sanctioned I/PM for in-service defibs at annual intervals?
I have always gone for 90 days, myself.
But yes:- "what does it do"? Then "test what it does" is a nice idea to bear in mind. As we know, some folk can get a bit carried away with testing kit to the nth.degree.