Writing unit tests is easy with Dlang. Unfortunately when you have a big collection of unit tests, it get's hard to maintain and debug them. In order to avoid these problems, you can use this flexible test runner for D programing language. There are many test runners for DLang and there are a few of them that have a lot of useful features that helps you to be more productive. Sometimes you need to use a custom feature that is not embedded with those libraries. Maybe it's about a custom test report, a new discovery mode or an integration with a third party app like an IDE or Jenkins. In each of these cases you need to dig in a project that is not maintained or you need features that does not match the creators view about this subject.