There is a new effort underway in order to improve code quality of X3DOM. In addition to the more casual functional tests, we started flesh out some unit tests for portions of the library code. You can run the tests in your browser by visiting this link.
Test coverage is pretty low at the moment and we need help from the community to continuously improve that. Interested in getting involved with X3DOM? This is a very good opportunity to start. If tackling Unit tests seems too adventurous to you, no problem, the documentation needs some work as well.
In order to get involved, please contact us via the developers mailing list.