I'm looking to introduce automated unit testing to a large body of existing Oracle PL/SQL functions, procedures, and types. I would like to use an existing framework that is conceptually as close as possible to JUnit. Free-as-in-beer is required. Apache 2 or similar open source license is a plus. The framework must work in Oracle 10 and 11. Anything that requires changes to the code being tested isn't an option. Active development and strong community support are desired.
What frameworks are available that at least come close to this description?