They do (usually). You can even get credit for it, at least in the US, it called CLEP - https://clep.collegeboard.org/. Cheapest year of college I ever had - was around $200.

I skipped an entire years worth of useless general ed courses to get my "requirements" to graduate out of the way at my college on 6 CLEP tests. I think the notes I took for those tests reading the wikibooks and wikipedia articles on the various topics on those tests were some of the best domain information notes I've taken. I also wrote them online, so pretty much all my K-12 notes are useless, but I gave my CLEP notes to my extended family with notes they need to read the material themselves but I did a bunch of work already.