[MRG] Fix AttributeError tests for Python 3.11

[musicinmybrain]

In Python 3.11, the messages associated with some AttributeErrors have changed. Adjust the message patterns in affected tests to accommodate both new and old message styles.

See #753 for details.

Reference issue

Fixes #753.

Tasks

• Unit tests added that reproduce issue or prove feature is working Not applicable: existing tests were failing on Python 3.11, and adding a Python 3.11 pre-release to CI is out of scope for me.
• Fix or feature added Test fix only; no change to installed library
• Documentation and examples updated (if relevant) Not needed, I think.
• Unit tests passing and coverage at 100% after adding fix/feature Waiting for CI run; should be as good as it was before!
• Type annotations updated and passing with mypy No types changed
• Apps updated and tested (if relevant) Not relevant

[musicinmybrain]

I have tested this with a provisional Python 3.11 package in the Fedora build infrastructure, and confirm that it fixes #753.

[codecov]

Codecov Report

Merging #754 (2126bd9) into master (d945d13) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master      #754   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           28        28           
  Lines         8648      8648           
=========================================
  Hits          8648      8648           

[musicinmybrain]

It doesn’t seem like the CI failures could be related to this PR. Are they expected?

[scaramallion]

They look like failures due to upstream pydicom changes, so don't worry about it.

[scaramallion]

Also, thanks!

[musicinmybrain]

Thanks for the quick review!