It appears that unittest was changed to stop hoarding raw exception data,

It appears that unittest was changed to stop hoarding raw exception data,
saving instead a traceback string, but test_support's run_unittest was
still peeking into unittest internals and trying to pick apart unittest's
errors and failures vectors as if they contained exc_info() tuples instead
of strings.
Whatever, when a unittest-based test failed, test_support blew up.  I'm
not sure this is the right way to fix it; it simply gets me unstuck.