Comment by amirouche

I don't do the TDD like a waterfall. I don't do upfront all the tests, there is a discussion between the code (what express the business need) and the tests that "wraps" it inside a safe zone (what ensures that the behavior is the one intended). As such, as the idea grow, both the code and the test grow at the same time. Look at [0] to have an idea of how the tests extend the safe zone along the code.

Also, I much prefer a lot of nice unit tests over a lot selenium tests (which takes a lot of time to run).

[0]https://github.com/charlesthk/python-resize-image/commits/ma...