How long can the herpes virus stay “undetected” in the body. When can an STD test safely rule out the absense?

How long can the herpes virus stay in your body without showing up on an std test. What is a safe time frame to wait until it would show on a std test?
Thank you, I was also wondering, as far as test results go, would it be possible that the herpes virus could lay dormant in your body for not only months, but possibly years before showing up on a test…., or even getting any symptoms until then? Thanks again.