Hi, to make unittest more extensible and for issue 18765 (having a way to run pdb when tests fail), I would like to make TestCase aware of the command line arguments given to the TestProgram so they can adapt their behavior based on them.

I suggested this change on python-ideas (https://mail.python.org/pipermail/python-ideas/2019-March/055842.html) but it did not get much attention.

I'm opening a PR in the hope to get more feedback and will start writing documentation.

Please comment if this is not appropriate or regarding anything I might have not thought of.

Bumping this issue as issue 37873 that wants to add a new -j argument to unittest got some attention lately.

This PR makes the Test Cases aware of the command line arguments given to unittest.main() and is needed to add the --pdb argument proposed in issue 18765 to run pdb.post_mortem() when an exception occurs during a test.

Both this issue and #18765 would be very useful to augment unittest.

Since test modules can already be run in parallel, #37873 does not seem relevant here.  (And I agree with the intent of that.)

I would be reluctant to add a mechanism with no current use, so I would not apply absent a decision to add one.