For some time now, I’ve had concerns about the large automated test suites that are being written; some with hundreds and hundreds of unit tests. It’s great that people are taking test automation seriously and writing lots of unit tests. Once developers get on the bandwagon they tend to write large numbers of unit tests and it feels good to see the number rise. It gives you a sense of confidence. I’ve seen this in my own team. Once the developers started writing unit tests they didn’t know when to stop and we ended up with a large unit test suite. The problem is that unit test suites need to be maintained, just like production code. Also it takes time and effort to write the unit tests in the first place. So the questions in my mind are: are all these unit tests actually catching defects and do we need to write quite so many? Of course others have thought of these same questions and I’ve come across a couple of blogs that have some great ideas on how we can get the most out of a un