I tend not to use my body parts for testing, only having just so many of them
Fingernail test. Not useful to me. All of my edges easily pass this test so why bother. Too easy.
3 finger test - while I don't use it, it tends to favor a 6k edge that has been deburred by running the edge through something. The microserrations left by removing a burr this way is the toothiness that gives it a passing grade. A more refined edge just cuts and doesn't warn. A serrated knife will pass this test quite well. A good 10k edge has trouble with this test.
Drawing the edge of the nail is useful for detecting chips that are hard to see without a loupe. Quick and useful. Not a sharpness test.
Using the edge for the task specific purpose intended - yes. Not always convenient and I would have too many piles of veggies doing this all the time
Shaving test(s). Just shaving arm hair is only slightly tougher than the fingernail test. Too easy. Shaving arm hair with the blade not touching the skin - hair whittling and hair popping (can't whittle because the hairs 'pop' before they can be whittled). Cutting the hairs without bending above the skin. Interesting tests and of use, but I rarely use because I don't like using my body parts for testing and want to at least appear somewhat normal to the public
There is also a WIDE variance in hair thickness.
Mostly I use push and slice cutting paper and use copy paper. An Honest push cut - no acceleration straight down - and measuring the distance from the pinch point is quite useful and easy to perform. Must be a DRY blade. 2 inch push cuts are quite sharp in anyone's book and 1/2 inch is reasonably good. You can use zig-zag cigarette papers, phone books, etc - all different. Pick something you can get a lot of and standardize on it.
Toilet paper - for scissors, can it cut a single ply of 2 ply toilet paper?
Paper towels - this is a structurally weaker paper and favors testing for toothy edges. Slice cutting holding only one side is a useful test. A rolled up paper towel tests for a toothy edge nicely - it should cut through the roll with only the weight of the knife upon it. Not toothy enough and it glides over it.
Dumbest test I know is to test for a 'wire edge' holding a blade perpendicular to a moving leather belt on a belt grinder. Popularized by a guy who has no idea what a wire edge is, but considers himself an authority on the subject. One guess who that one is LOL.