Cosmetic clean-up of the pytest fixtures in tests/unit/conftest.py

[bernhardkaindl]

This only changes the refactors file tests/units/conftest.py

• it is the local pytest fixtures for this directory
• and the changes do not break the tests in any way.

For a clean review, I refactored the Refactoring part from #67 into the PR.

It follows the TDD model of

• Add failing test
• Fix the code and switch the test to pass
• Refactor (this PR - but these are only cosmetic updates) <---------------------------

Everything here already has 100.00% code coverage (the every file in tests/unit/* is 100.00% covered)

It is split into two commits, the 1st for actual refactoring:

• nothing is moved
• just tiny improvements from review comments

And the 2nd commit is only comments and docstring clean-up to shorten them - doc is n #68.

---

• This PR contains two overlapping commits on the same file,

• conftest.py is the local pytest plugin, used only by the tests in tests/unit, it does not change the product itself.

  • See the new, proposed README.md for more information what the conftest.py contains:
    https://github.com/xenserver-next/status-report/blob/add-tests-unit-conftest-README.md/tests/unit/conftest-README.md

Commits:

• tests/unit/conftest.py: Minor refactoring of the test fixtures

  • Apply code refactoring from reviews:
    • Change 1 and 2: Use if-expressions where applicable
    • Change 3: For consistency, add the imported module to sys.modules for Py2 as well
    • Change 4: Change import_bugroot into a yielding fixture. After return,
      • reset the bugtool.data dict and
      • reset sys.argv[] to a good default argument as clean-up.

• tests/unit/conftest.py: Shorten docstrings to fit into 88 columns

  • Clean-up the docstrings and comments
  • Shorten the commits to fit into 88 columns,
    • Plan: The goal is to transition to shorter page width of the code.
  • Clean-up not important comments and docstrings, see:
    • Docs-only: Add tests/unit/conftest-README.md documenting tests/unit/conftest.py #68 for a dedicated README.md for tests/unit/conftest.py)
    • It provides the reference documentation using these fixtures in tests now.