Or they can run it, asking the real arbiter of truth whether it works or not.
Of course, "whether it works" is merely one (very important) metric of quality.
Can you work with this person? Can you collaborate to write code, or will it be a daily struggle?
Whether the code actually builds and runs after the hour is up does not help answer these questions; it is arguably the least interesting part of the whole process. The time limit is artificial; if all the other things align but you didn't happen to get it working in one hour, you'll likely have got it in two. If they don't align, you'd likely never have got it.
This is like writing code in notepad and creating a PR without building or running it to test once. What is this testing? There is no real world scenario where you are expected to work like this and for a good reason.