How do duolingo tests work?
It depends on the test you're talking about. You can purchase a Spanish progress test, which will measure your progress and help you find the places you are in need of help with and places you have mastered. You can also purchase a timed practice test, which, when enabled, will help you strengthen specific skills to keep your tree golden. It's been awhile since I've been to the Duo store but as far as I know, those are the only tests. Hope this helps.