Unit Testing Your Architecture With ArchUnit
I am a Spring/Java developer (primarily) and an advocate of unit testing. My co-workers have created some great blog posts on unit testing (especially for Java) for those who are also interested in the subject.
There is often a debate over what constitutes a unit test, an integration test, a system test, etc. But, most of us agree that tests keep you from going "off the rails" once a project becomes sufficiently complex.