Here's my trouble with testing as espoused by proponents of TDD: I bought into the Agile Manifesto. I believe in working code over specifications. How then, am

Here's my trouble with testing as espoused by proponents of TDD: I bought into the Agile Manifesto. I believe in working code over specifications. How then, am I supposed to write a bunch of tests that will in turn tell me what code to write? It is not a coincidence that one of the reasons TDD'ers love rspec so much is that the "code reads like documentation" - it's even called r spec. Perhaps that is ok for mature projects. But I often hear TDD and agile used together as if they weren't in conflict and I get confused. Then again, I've only ever worked on new projects. Maybe I'm missing something?