I rarely learn algs that aren't stupidly easy (e.g. I only recently learned
these two OLLs, and they took about 5 seconds each), but when I do, I get a countdown timer, set it to something like 1-3 minutes depending on how difficult it is, and do the alg constantly (looking at it if I can't remember it). Afterwards, I try it without looking at it. I do it however many times it takes before the cube is solved. If I don't DNF it doing that, I'll usually say I've learned it, unless I'm not entirely sure. If it's part of a small set of algs (e.g. one COLL set), I'll go through that set to make sure I get recognition right and don't confuse it with a different case.