This is something I have been thinking about. Should proposals add a conformance test XML file for the behaviour of the proposal like is available for XPath and XQuery?
Some advantages to this would be that it would help making different implementations consistent, and make it easier to add the proposals to the existing test suite.
They should ideally be in the same structure as the test suite (prod/[GrammarSymbol].xml) to make it easier to run the tests and add them to the QT3 test suite.