Why Speed Is Important

Speed as a measure of quality

Before we explain how we’ll use this information to speed up our tests, let me make a pitch for the idea of being a little obsessive about test speed.

We’re going to run our tests a lot.

If we’re doing the kind of rapid-feedback TDD that we’ve been discussing up until now, we’ll be running at least a subset of our tests nearly continuously, multiple times an hour. (Any exact number that we put here is going to seem shockingly high to people who aren’t used to super-fast test feedback and shockingly low to those who are). And we’re probably not the only developer on our team. Also, ...