[majelix]

> It either relies on a waterfall-like process where the full design is known before-hand and therefore what tests have to be written,

This is that fuzzy line between behavior driven development and test driven development. Sure, you may not be able to write cukes to test how that your social mortgage site is going to work, but you probably should be writing tests to ensure that your internal compound interest code is correct.

[sambeau]

I say exactly that in my comment. I'm not suggesting that tests shouldn't be written — I'm suggesting that tests shouldn't be re-written without just cause.