When writing the unit tests for running doctests from inside a zipfile,
I initially had "<anon>" as the name being passed to the
doctest.DocTestFinder.find method.

With that name, the line numbers coming back for all of the examples
were being incremented by 1 beyond what test_doctest expected (and hence
my tests were failing).

Changing the name to "anon" eliminated the errors. (Both "<anon" and
"anon>" also failed in the same fashion as "<anon>")

I suspect there may be a problem with __LINECACHE_FILENAME_RE when "<"
or ">" are embedded in the name used for the doctest execution.