Experience with FIT08 Jun 2007
I have just discovered an old post by Jim Shore (http://www.jamesshore.com/Blog/How-I-Use-Fit.html) about how he started out using FIT. He started out by switching from a unit test driven approach to a more story driven development approach.
I encountered a big problem with this approach, though: I stopped doing good TDD. "Storytest-driven development" blurred the line between Fit and unit tests. The "STDD" cycle largely replaced the TDD cycle and, as a result, I had far fewer unit tests than normal.
That was a problem because Fit examples are not unit tests. Fit examples are just that: examples of a business rule in action, from a business perspective. In TDD, I write tests for every line of code that can possibly break. In my Fit examples, I try to talk about every possible business case. That's a bigger net than TDD, and without TDD, my code wasn't well tested.
I had the exact same experience. I also found that the design suffered due to the lack of tests (it did not force me to refactor as often as I should) and it had a detrimental impact on my productivity. Story tests are larger in scope and take longer to run. Unit tests provide a much faster feedback loop when you break something.
I wish I had read this before I started using FIT.