Thanks for updating the patch, I'll try to take a look at it soon (within a week or so).  If anyone else wants to take a look at this, feel free.

> Why doesn't regrtest give an error if it doesn't run tests?

regrtest can't know the difference between an old style test which executes on import and a new style test which has a test_main.  This is why I want to get rid of all the old style tests (the ones that execute by side-effect of import).  Then we can have regrtest complain if there is no test_main method just as you suggest.