Is This Better Than a Unit Test?

You can actually test it against the real production system. You have a thing that this is what we want it to do. We've refactored it into we've kept the original, but we've made a new thing that's supposed to have the same behavior from it. And so now you can compare the two. Is better than a unit test, right? Because you know what you want your system to do. That's in addition to being able to run it right away and check out your intuition and see if it works the way you expect.