Question

Does anyone have metrics on the utility of formal Unit Testing? I see a lot of attention being paid to unit testing tools and I was curious why?

I stopped formal unit testing over 5 or 6 years ago and the net gain in productivity seems quite high. I stopped unit testing because I noticed that it never caught anything – let alone anything useful. The type of errors that unit testing detects seem to be preventable by not drinking more than 2 glasses of wine/beer per hour (or 2 joints per hour). Also – unit testing seems to create risk by allowing the developer to think that there is some safeguard to catch their mistakes.

I do test to ensure that the code works as it should, but I do not use any tools. I test based on the changes being made. My production error rate for new code is approximately zero. My error rate for changes to code is about 2-3 bugs per quarter. The above measures are based on 4 production applications that I develop/support.

Answer 1

Here is a thread that has some research about the TDD approach Research on TDD

Is there hard evidence of the ROI of unit testing?