It would be useful to be able to check that there are tests that cover all the code paths, especially in import-mbox.py and archiver.py.
It should be easy enough to test import-mbox.py (at least for the parts that handle mbox files), as it can process lots of different input mails in one run. Though there are also CLI options to consider. It may be more difficult to test archiver.py as that handles one message per run. However, I guess most of the important parts of archiver.py should be exercised by the import-mbox tests.
