Testing mulitple versions of dateutil

In response to this question on the Boston Python Slack:

Any idea why dateutil’s parser would parse “23APR2019” just fine on my Windows install of (Python) 3.6.8 but not in an install of (Python) 3.7.x on another OS?

Somebody suggested:

Check that you really have the same version of dateutil in both places.

I thought it might be quick/fun to determine if the version of dateutil could be the problem by running a simple test in multiple versions of Python using tox. That turned out to be the case, so for more fun, I ran the same test in nox. I used pyenv to install multiple versions of Python.

TL;DR:

  • The format isn't parsed in dateutil < 2.7
  • nox is cool