tests: address post-merge review feedback

[filiplajszczak]

This follows up on a couple of useful Copilot review points from already-merged test PRs.

It addresses the factory-test feedback from #320 by resetting Inverter.num_inverters per test and by loosening the unknown-type assertion so it no longer bakes in the current typo in the production error message:

• tests: add inverter factory coverage #320 (comment)
• tests: add inverter factory coverage #320 (comment)

It also addresses the #321 feedback on test_production_offset_initialization_default, which was still constructing a fresh Batcontrol(...) outside the patched fixture setup:

• tests: clean up pytest configuration and setup #321 (comment)

[MaStr]

Hi, thanks for following up on these points.

I was not sure, if you are pro or contra the copilot review, that was the reason I took the comments as a 2nd opinion and not mandatory.

In the future, I'll keep the copilot review as a additional opinion. In the past, it made good review points on my changes, too.

[Copilot]

Pull request overview

Follow-up test-only changes to incorporate post-merge review feedback, improving isolation and robustness of the existing test suite.

Changes:

• Refactors test_production_offset setup to construct Batcontrol instances via a factory fixture and ensure shutdown happens for all created instances.
• Adds an autouse fixture in inverter factory tests to reset Inverter.num_inverters per test for deterministic behavior.
• Loosens the unknown-inverter-type assertion to avoid coupling to the current production error-message typo.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
tests/batcontrol/test_production_offset.py	Introduces a make_batcontrol fixture to ensure instances are created within patched factory context and reliably shut down.
tests/batcontrol/inverter/test_inverter_factory.py	Resets global inverter instance counter per test and relaxes the error-message regex match for unknown types.