Notebook test is broken at head.

[dabacon]

See PR #4080 The Notebook Tests against PR test fails for a PR with no real change in the PR.

Exception encountered at "In [13]":
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
/opt/hostedtoolcache/Python/3.7.10/x64/lib/python3.7/site-packages/ipykernel/pylab/backend_inline.py in configure_once(*args)
    167             def configure_once(*args):
    168                 activate_matplotlib(backend)
--> 169                 configure_inline_support(ip, backend)
    170                 ip.events.unregister('post_run_cell', configure_once)
    171             ip.events.register('post_run_cell', configure_once)

/opt/hostedtoolcache/Python/3.7.10/x64/lib/python3.7/site-packages/IPython/core/pylabtools.py in configure_inline_support(shell, backend)
    384     )
    385 
--> 386     from matplotlib_inline.backend_inline import configure_inline_support_orig
    387 
    388     configure_inline_support_orig(shell, backend)

ImportError: cannot import name 'configure_inline_support_orig' from 'matplotlib_inline.backend_inline' (/opt/hostedtoolcache/Python/3.7.10/x64/lib/python3.7/site-packages/matplotlib_inline/backend_inline.py)

[dabacon]

I suspect this is coming from IPython 7.23 see the release notes here
https://ipython.readthedocs.io/en/stable/whatsnew/version7.html

[dabacon]

Testing adding matplotlib-inline as a dependency in the requirement file for the test.

[dabacon]

Testing adding matplotlib-inline as a dependency in the requirement file for the test.

Did not fix.

[balopat]

I opened ipython/ipython#12941 - downgrade to ipython==7.22 fixes it, they released 7.23 yesterday, hence the breakage. #4082 will fix it temporarily by pinning to 7.22

[balopat]

Some more color: from this discussion https://www.reddit.com/r/voidlinux/comments/n2nxyd/matplotlib_inline_broken_after_most_recent_update/gwky6c9/ and this PR (void-linux/void-packages#30616) it seems it's a bug...but we'll see, for now I think we can safely pin to 7.22. If ipython takes https://github.com/ipython/ipython/pull/12940/files then we'll be fine probably with 7.24.

[balopat]

This is now fixed in #4077.