I do a slam test, safety test and drop test.
Slam test so striker doesn't follow down. That one is my most common failure but that's because I was crowding the limit in the first place.
Safety test is set safety, pull trigger then flip it off fast and repeat until I get bored. It doesn't hurt to work the bolt a few times in there too. I fixed a few that failed on release, most were brought to me that way. Recently I found a bad safety on a Sako, and it wasn't really because of the trigger adjustment. Even worse it was my own. If I pulled the trigger hard it dropped the striker. Turned out to be the soft piece of sheet metal that passes for a trigger block being a hair too narrow. The fix is to take it apart and hit it with a hammer. Fun to say, not as much fun to do.
I do a drop test, which is just bouncing it on the recoil pad a few times and flipping the safety off briskly. It doesn't cost anything, and at least I know I've done all I can do. The hits aren't very hard, partly because most of my favorite rifles have striker blocking safeties that eliminate the trigger from the equation in the first place.