There is no foolproof 'test' IMHO. Fortunately local bike shops often have tester programs and that's about as close as you can come. After that comes experience, clothing choices, and ultimately types of bikes...

On my road bike I have the upgraded WTB Volt (found by using the test program at my LBS with several different saddles); on my go anywhere Salsa Vaya is a Brooks B17; and on my Specialized Fatboy the stock saddle that came with it. On my garage sale Raleigh C-50 is some sort of Bontrager saddle that's long out of production. They all work....but I'm not sure one would work on all bikes.

I may put the standard Volt that came on the Vaya on the Fatboy. Or not.

Of all of them, the Brooks is the most comfortable now, and by a long shot, but it sure would not have 'tested' well...the good thing about a Brooks though is if you need to resell it, you can probably get most of what you paid for it.