Battery Life and test

I do not own a macbook but looking to purchase a used one.
Is there a way to test or verify how many hours the battery can power the macbook without running the macbook on its battery until it dies?

That is hard to do if looking at used ones since I cannot keep it that long to test.

I use an app called Battery Logger. It will keep a history of charges and battery health., Run it for a week and you will be able to gage and track what your battery is doing.