The quickest way to determine if you’re UPS is working?
The quickest test is to pull the plug out of the wall and see what happens. If the attached load drops (ie computer turns 0ff) then you have a UPS or battery problem.
If everything is powered and keeps going, then your UPS is working! At the very least, you know your UPS and batteries are working. Of course you can perform calibration test, communications tests and much more, but this quick test will tell you that there’s some protection.