PR: Fix Pytest catching up tests using Spyder-unittest or VSCode

[maurerle]

Description of Changes

When Debugging in an editor with pytest support (for example spyder with spyder-unittest plugin, PyCharm or VS Code) the tests were not catched up.

This was due to the fact that there was

• an import error E ImportError: QtWebEngineWidgets must be imported or Qt.AA_ShareOpenGLContexts must be set before a QCoreApplication instance is created
• pytest_plugins in external-deps Defining 'pytest_plugins' in a non-top-level conftest is no longer supported:

Both is fixed in this commit allowing to run a single Test file directly from the IDE or even debugging a single test directly.
Before that, one could only run a single test using pytest testfile.py instead of the whole suite

Affirmation

By submitting this Pull Request or typing my (user)name below,
I affirm the Developer Certificate of Origin
with respect to all commits and content included in this PR,
and understand I am releasing the same under Spyder's MIT (Expat) license.

I certify the above statement is true and correct: Florian Maurer

[ccordoba12]

Thanks @maurerle for your help with this! I left a couple of small suggestions for you, otherwise looks good to me.

[ccordoba12]

Thanks @maurerle!

Note: In the future please add all suggestions to the batch, so they are pushed in a single commit. That's described here:

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/incorporating-feedback-in-your-pull-request