Spring is an essential part of my technology stack. I cann’t image providing quality software that doesn’t leverage an IoC container. However, decoupling components requires some amount of configuration. Whether this is accomplished through annotations or XML, it’s fairly easy to mess up. Fixing these missing or incorrect configurations doesn’t take very long. The real question is how quickly can you identify these errors?
This question of how long, is a feedback loop question. Unfortunately many teams wait until they fire up the application server to see if their Spring context is wired correctly. This is too late.
One of our clients suffered from this very issue. Due to environmental constraints they could not run automated, in-container tests that would have identified misconfigured beans. After repeatedly committing stupid configuration mistakes, I decided that I would write a Spring wiring test. As I began to write this I encountered five problems.