Code review comment for lp:~vila/bzr/321320-isolate-doc-tests

> If someone (mgz ?) really feels strongly about adding more
> isolation to doctests then feel free to do so, I've prepare
> things a bit by adding two functions isolated_doctest_setUp and
> isolated_doctest_tearDown that accept a 'test' parameter so it
> should be possible to force them to run in a tmpdir.

This may as well land if it fixes the problems with doctests people are actually having, even if it's not a complete solution.

Anyone with for instance, a plugin that adds a hook and doesn't run selftest with --no-plugins will still risk random behaviour though right? I'd like a note in the developer documentation saying doctests are not as robustly isolated as general tests.

Do you also want to uncomment the doctest we disabled the other day in this branch?