To help keep beanbag-docutils maintainable, a tox.ini has been added

to run the entire test suite against every supported combination of

Python and Sphinx.
Right now, we support Sphinx as far back as 1.8, for some of our older

codebases. So, this tests against each X.0.Z and the latest X.Y.Z of

each version series of Sphinx. We'll be dropping most of this in

beanbag-docutils 3.0.
Until then, some fixes have been included to make beanbag-docutils run

on some older versions of Sphinx, including the in-progress Sphinx 6

(which, currently, just requires unit test fixes).

All unit tests pass across all supported versions of Python and Sphinx.