Isn't it simple? Passing unit tests by definition don't guarantee that your software works. Passing system or acceptance tests do.
Unit tests are still nice to have, which DHH doesn't seem to oppose. Along with good documentation, good unit tests may help keep things maintainable for developers themselves. But they are far from essential, so depending on time constraints and project complexity they may just not make sense to spend resources on.
Unit tests are still nice to have, which DHH doesn't seem to oppose. Along with good documentation, good unit tests may help keep things maintainable for developers themselves. But they are far from essential, so depending on time constraints and project complexity they may just not make sense to spend resources on.