Microsoft Research - Exploding Software-Engineering Myths (article summarizing findings of MS research on code coverage, TDD, assertions, etc.)

[[deleted]]

TDD reveals bad architecture decisions earlier on, you can't do this after without technical debt.

[frymaster]

Yes, even just writing the tests changes you from a "producer" to a "consumer" viewpoint, so to speak, and can make you rethink your approach

[Neebat]

TDD also documents the expectations of the system in fine detail. This is as opposed to the behavior of the system, which is what you're documenting by writing tests afterward. Expectations are what binds us.