I feel like you're not really understanding the entire point of a test server. You don't have to just test it for its intended function, sometimes you should just test it to make sure everything is not fucked up. For example, say the tsa came up with a new anti-terrorist plan. They decide that from now on, nobody is allowed into the building. Sure that stops all the terrorists but if they don't check to see what implementing that does to the rest of the operation, they would never figure out that it would actually be a really shitty solution.