I am reading about Alistair Cockburn's Hexagonal Architecture with interest.
One claim he makes is:
Finally, the automated function regression tests detect any violation of the promise to keep business logic out of the presentation layer. The organization can detect, and then correct, the logic leak.
I do not understand this point. Is he saying that because the test is headless, then calls to a UI layer will throw exceptions? That doesn't seem to be a very sound test!