I think you're referring to the part in the book where Ousterhout says he doesn't like to start with a test harness when writing a new abstraction or feature like some advocates of TDD would. I think that was some of the best advice in the book in my opinion.

Instead, Ousterhout recommends designing the interface for the abstraction you're building before you start writing a test harness for it, and I can't agree enough with that statement.

If you write a good interface, testing it will be easy. If testing the interface isn't easy, then you have a bad interface. (This is relative to the complexity of the code invovled, obviously)