Configuration testing for Java developers: a case study

Andrew Satarin has given a talk on recent Heisenbug about how to cover configuration with tests. Thanks to Andrew, we've been already doing it in our projects for 3 years now, and it was proved as a very useful idea, which helps us to catch many potential deployment issues early. But the idea of testing configuration is also quite new, with "best practices" yet unknown, thus write and support such tests could be a bit of challenge. I want to share our own experience as Java developers: how we write Java unit-tests for configuration, how we benefit from them, pitfalls and workarounds.