More like glorious documentation: verified to be up to date... and has examples.
As others mentioned, regression testing is about the only really useful correctness step. There's also motivation, to keep on track for what is actually needed. Also it helps you write an API, rather than just implementation: the tests are a client. (On the downside, these extra clients depedence on your API, also make it more work to change that interface, giving it more inertia). Plus: who shall test the tests?
NB: I'm not a TDD adherent, never used it, so take what I say with a grain of salt: it's just my own reasoning + what I've heard from people who've tried it.
As others mentioned, regression testing is about the only really useful correctness step. There's also motivation, to keep on track for what is actually needed. Also it helps you write an API, rather than just implementation: the tests are a client. (On the downside, these extra clients depedence on your API, also make it more work to change that interface, giving it more inertia). Plus: who shall test the tests?
NB: I'm not a TDD adherent, never used it, so take what I say with a grain of salt: it's just my own reasoning + what I've heard from people who've tried it.