I agree insofar as writing that sort of test prior to writing code that makes your tests pass is a good thing. I don't think that matches the popular definition of TDD though. Most TDD advocates will insist that a key facet of TDD is that NO code exists in your application without first writing a test first. Given that, you're forced either into doing the highly detailed unit tests, or having an integration suite that needs to accomodate for every potential edge case of the entire system underneath it, which for anything non-trivial will be extremely time-intensive to run.
