pytest: Add support for pytest-8.2 on Python3.11 (color, verbose)

[bernhardkaindl]

Update support for testing using pytest:
Add support for pytest-8.2 on Python3.11 (color, verbose)

This change supports the different assertion diagnostic output that pytest-8 produces:

The assertions from pytest-8 include escape sequences for colouring the output nicely, and to pass both, the string that we expect to find in the assertion needs to be shorter.

For pytest v8 to produce the assertion messages that this test expects, we need to add -vv to the default pytest options to enable more verbose assertion messages.

By default, also show the local variables in the traceback of an test exception: Add --showlocals to the default options.

[coveralls]

coverage: 93.035%. remained the same
when pulling 6d0fcd8 on xenserver-next:add-support-for-pytest-8.2-with-python3.11
into 2bc9efe on xenserver:master.