Peter Arrenbrecht's Blog

When using components decoupled by queues or other intermediate data stores, it can be a pain to trace the origin of faulty data in the queue. In languages with decent support for stack traces, however, it's easy. In Java, you just add a temporary field public final Throwable createdBy = new Throwable(); to the class in question. Or, if you need to know who enqueued it where, you vary the creation of the Throwable accordingly. (See example 8-5 of logging in the Red Hat Web Application Framework, too.)

What I termed documentation-driven testing has before been penned literate testing , where the Python docTest people have summarized the essence very nicely indeed.