Concordion

Concordion is an open source framework for Behavior Driven Development (BDD) that enables developers, testers and business analysts to build executable specifications in free-form using plain English. A Concordion active specification consists of two parts: a well-formed XHTML document describing the functionality, and fixture code written in Java (a special Concordion extension of a standard JUnit test case) that finds concrete examples in the document and uses them to verify the system under test. Concordion acceptance tests are so readable, they can double up as system documentation. And, since the tests run against the system, you can be confident the documentation is always up-to-date.