I've worked on quite a few different large code bases. I agree with the author 100%. Tests are a tool. They are a particularly useful one, but they are just a tool. Unit tests are significantly less useful than TDD folks would have you believe when compared to things like integration tests. And integration tests are vastly more costly than what TDD folks would have you believe. Personally, I much prefer gold file tests with manual inspection when it comes to test automation. I've seen large compiler projects that get by pretty far with just that. Never mind things that make no sense to test: Like "Is this game fun?"