Instead of just writing unit tests which test that modules work as expected, I think we need a slightly new test framework to write tests that will check if compiled addon outputs actually work on the intended platform (ie Firefox). For example, the simple-prefs module has two types of tests, the unit tests written in JS that test the module exports obj, and the compilation tests written in Python to test the generated xul file looks correct by parsing it. What I would like is a third type of test that would test that the generated xul file works like it is expected to after it is installed. An example test would do this: 1. install test addon 2. naviagte to about:addons page for the addon 3. Confirm the desired prefs are displayed in the desired order. 4. change prefs and confirm that the simple-prefs module is observing the changes 5. change prefs with simple-prefs and confirm that the changes are reflected in the about:addons page for the addon.