CI is green but I've realized that we don't have Py 3.10 in CI yet so I'm gonna run the tests with the release candidate locally.

I'm afraid that there is more than one test failing and it seems that the other failures have something to do with jedi which is not compatible with Python 3.10 yet. Will have to investigate it more.

This PR now solves all problems with Python 3.10 I know about. All tests are passing in my local environment with Python 3.10rc1. Also, the full compatibility depends on the similar fix for jedi: davidhalter/jedi#1795

Thank you so much, @frenzymadness ! Can you also add a 3.10.0rc1 excursion to CI? It appears these are now available.

It seems that the nose is not compatible with Python 3.10. and it's abandoned for quite some time so I don't expect anything. Is there any plan to drop it? We might run pytest first and then iptest/nose. Also, the tests will fail until jedi is fixed.

It seems that the nose is not compatible with Python 3.10. and it's abandoned for quite some time so I don't expect anything. Is there any plan to drop it?

Yes, I'm currently trying to get some funding from NF to hire someone to do the bulk of the work.

Some modification to ipykernel will be needed too as it import things from IPython that rely on nose.

Some modification to ipykernel will be needed too as it import things from IPython that rely on nose.

I might be able to help with that effort. Could you please tell me more? The ultimate goal is to get rid of the nose entirely and port all the tests to pytest, correct? What is nose used for in runtime?

Most of nose use-case are nt.assert_equal, nt.assert_in and similar, there are bout 900 of those in the codebase:

$ rg -tpy ' nt\.assert_' | wc -l
     926

That's the easy part, there are a bunch of utils, like @skipif(....), that are relatively straightforward to migrate to pytest,
and finally there is all the mess that is in IPython/testing/iptest.py and IPython/testing/ in general that run some IPython specific code (as IPython is itself an interpreter there are some hacks to do).

It's likely portable to pytest, but need some time to actually focus on that.

Good news is the test suite is old (20 years or so), and therefore I think that many of the test are not useful anymore, so if some tests can't be ported and need to be removed, it's ok. Also most of the functionality in iptest can be nuked as it pre-date having CI and was dealing with parallelizing the test and stuff like that.

I'll open a more specific issue and list all the tasks that need to be done for removing nose a a dependency.

Thanks for the PR, I incorporated your work in #13282 which got merged.