The answer to 'how to test surge protection' is to use a surge protector tester to check if your surge protector is functioning properly. Surge protector testers are inexpensive devices that you can plug into an outlet and then plug your surge protector into it. The tester will indicate if the surge protector is providing the proper protection.
It's recommended to test your surge protectors every 6-12 months to ensure they are still working effectively. Over time, the internal components in surge protectors can wear out, reducing their ability to protect your electronics. If the tester indicates the surge protector is not working, it's time to replace it to maintain proper protection for your valuable devices.