I usually like to ask the following question when I’m interviewing developers:

Imagine that you have a task that you estimated to be 2 weeks. It’s now two weeks from the deadline and you realise that you’ve made a mistake and that the task will take 3 weeks to do. What do you do?

The question is vague on purpose and usually shows how mature the developer is.

In the past 6 years I’ve worked on web applications in Rails, Clojure, Java and back to Rails. This is an overview of these past years, the benefits of working with such different tech stacks, and also it’s drawbacks.

I never worked on a project with 100% code coverage. I’ve worked on several projects with a high coverage and a test suite that gave confidence to the team. But even on those projects sometimes we’d have a nasty bug in production that could have been easily detected with a simple test.

This is a tricky subject and usually developers don’t care much about this or think that it’s not worth the cost, or even that is not that useful. I’ve gathered here several arguments in favor for a full coverage.