Depends on what you're testing it for be it spun/blown or getting there.
The first test would be what's in your oil, if there's chunks of metal the size of Kansas in it, then you've got problems.
If it's clear then you shouldn't worry too much.
There really isn't a way to check and see if the bearing is getting worn or is in danger of failing.

If you're still concerned, take out the plugs, pull the cover off and rotate the engine manually.

If you hear abnormal noises (outside of a little piston/jug noise) you either have some wonky stuff going on with CCT or something else. Vague, I know, but trying to diagnose one spinning thing inside an engine with lots of moving parts without looking at it is difficult.

High movement parts like bearings tend to make a considerable amount of noise when they fail.