Wrap unittest method test in TestSuite

[alexander-yu]

For #3252

• Pull request represents a single change (i.e. not fixing disparate/unrelated things in a single PR)
• Title summarizes what is changing
• Has a news entry file (remember to thank yourself!)
• Unit tests & system/integration tests are added/updated
• Test plan is updated as appropriate
• package-lock.json has been regenerated by running npm install (if dependencies have changed)

This PR addresses something I noticed in #3252, where clicking Run Test for a single unittest method (when choosing unittest as the test framework) leads to setUpClass not being run, even though it does occur when running Run Test for the entire class.

Looking through the test launcher, it appears that if we're running a single test method, then we actually end up running a bare TestCase object, whose run method (which is called by the unittest test runner) only calls setUp. Wrapping the TestCase object with a TestSuite class ensures that setUpClass is called.

[d3r3kk]

This is a great change, I think we should ultimately accept it, thanks!

However, could you add a test plan for this adjustment to the Python code? We don't have unit or system tests set up (yet) for Python files in our extension - something I hope to rectify in the next quarter.

A test suite that would show the behaviour without your change would be one where tests fail if the suite initialization method is not called first. Please add this to .github/test_plan.md.

Also, please add a news entry for your PR (remembering to thank yourself) and I will accept.

Again, thanks!

[alexander-yu]

Sure thing! I'll see what I can do.

[msftclas]

All CLA requirements met.

[alexander-yu]

@d3r3kk modified the test plan + added news entry; also merged the newest upstream changes.

[d3r3kk]

Thanks for finishing up @alexander-yu! I will take this up with the team tomorrow and see if we want to include it for the next release after our mid-December.

[d3r3kk]

🎆

We've merged the change, will be included in the upcoming release for Dec.