add code coverage options

[jmartin-tech]

Enables usage of the pytest-cov plugin to limit coverage number to project source code in the garak/ path.

Quality of life entry for exploring test coverage values. Restricting the output to library code without including the tests/ path requires configuration be place in a settings file so pyproject.toml is elected as already available in this project.

Output of coverage is similar to:

---------- coverage: platform darwin, python 3.12.4-final-0 ----------
Name                                            Stmts   Miss  Cover
-------------------------------------------------------------------
garak/__init__.py                                   3      0   100%
garak/__main__.py                                   7      7     0%
garak/_config.py                                  141     12    91%
garak/_plugins.py                                 238     32    87%
...
garak/resources/theme/__init__.py                   3      0   100%
-------------------------------------------------------------------
TOTAL                                            7744   3029    61%

Verification

• Run with the following:

python -m pip install pytest-cov
python -m pytest tests --cov

[jmartin-tech]

For now this does not add pytest-cov as a test dependency though I am open to expand this to have it become part of dev test requirements.

[leondz]

Let's expand it

[leondz]

btw, what's a good hook for automation?

[jmartin-tech]

For automation, initially flags could be added to output coverage as html when running linux tests on main only.