CI/Python: Add reporting of code coverage from PyTest

[bernhardkaindl]

• Gather code coverage results from pytest and upload to Codecov.
• Add minimal configuration file for pre-commit and run it in CI
• Appy an example pre-commit fix for scripts/examples/python/XenAPIPlugin.py:
  • As it is a module, not a script, remove the shebang and add a module docstring

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

❗ No coverage uploaded for pull request base (master@2a991fe). Click here to learn what that means.

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #5384   +/-   ##
=========================================
  Coverage          ?   44.70%           
=========================================
  Files             ?       18           
  Lines             ?     2982           
  Branches          ?        0           
=========================================
  Hits              ?     1333           
  Misses            ?     1649           
  Partials          ?        0           

Flag	Coverage Δ
python2.7	50.88% <0.00%> (?)
python3.11	49.31% <0.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[psafont]

pytype is spitting out quite a few errors, but the check remains green. IMHO it should be made a fatal error. not sure how to separate it from the other checks in pre-commit

pytype_runner: File "/home/runner/work/xen-api/xen-api/scripts/test_usb_scan.py", line 139, in test_usb_exit: Function TestUsbScan.assertIn was called with the wrong arguments [wrong-arg-types]
pytype_runner:          Expected: (self, member, container: Union[Container, Iterable], ...)
pytype_runner:   Actually passed: (self, member, container: int)
pytype_runner:   Attributes of protocol Container are not implemented on int: __contains__
pytype_runner: For more details, see https://google.github.io/pytype/errors.html#wrong-arg-types
pytype_runner: ninja: build stopped: subcommand failed.
Error: Function TestUsbScan.assertIn was called with the wrong arguments,          Expected: (self, member, container: Union[Container, Iterable], ...),   Actually passed: (self, member, container: int),   Attributes of protocol Container are not implemented on int: __contains__ https://google.github.io/pytype/errors.html#wrong-arg-types (you should find an entry in the pytype results with links below)

[acefei]

Agree with @psafont mentioned in #5365 (comment), packaging the file would make it more convenient for future use.

[github-actions]

pytype_reporter extracted 49 problem reports from pytype output.

You can check the results of the job here

[psafont]

With the current issues in the porting procedure, I'd rather add the pytype_reporter rather than waiting for it to be published as a package

[edwintorok]

This is mostly CI code, and the CI is all green. I haven't done an in-depth review for the CI code, but if we find any problems we can always easily fix it.
The actual change to product code is tiny, and that looks fine.