Test-Driven Development: I Finally Get It

"Often if you get a decent suite of unit tests you are only a few requirements changes or change requests away from half of them breaking. Unit tests are software. That may sound trite but it’s worth remembering. The larger and more complex your unit tests, the more code you’ve written to implement a particular feature (the tests count in that metric) and that’s more code you have to change."

This is a huge objection I share, on projects I've worked on that have lots of unit tests, a lot of time ends up being spent on debugging the unit tests. That time is valuable and could be spent on making the application better.

The author doesn't really address this concern either, even though it was clearly a problem for him in the past.