Pytest Coverage TPI

[eleanorjboyd]

Refs: #22827

• macOS @bpasero
• linux @bhavyaus
• windows @rzhao271

Complexity: 5

Author: @eleanorjboyd

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In this TPI you will be testing the new coverage implementation for Python!

Find or create a python project that has tests and test coverage. Hopefully copilot can help you with this but you can also look at my testing example repo and specifically this test which will call my inc_dec.py file with functions: https://github.com/eleanorjboyd/inc_dec_example_repo/blob/main/inc_dec_example_test_suite/test_unit_and_pytest_combo.py. Additionally the vscode-python extension can run with coverage too (for some specific ones, they error and I am looking into it, I think the specifics of running tests which run tests while running coverage might be causing interference between the actual test cases and the reporting)

1. Create a venv using the "create environment command" choose python >= 3.8
2. In the terminal, run python -m pip install pytest pytest-cov.
3. From the command palette, run "python: configure tests", select pytest and then "." (root directory)
4. click the test explorer icon (beaker)
5. run tests with coverage using the button
6. look at coverage by clicking the beaker icon below the test explorer icon
7. create a function that has an "if / else" block, create tests so only one of those conditionals is met, make sure the UI shows the conditional you missed as not covered which will also appear red in the editor for that function.
8. try different things and make sure they react correctly, ideas like: comments (shouldn't count towards coverage), blank lines (shouldn't count), blank files (shouldn't count and coverage should be grey in the coverage tab)
9. in your settings.json you should see a "python.testing.pytestArgs": [], update this to include ["-cov=."] now make sure branch coverage is NOT included.
10. update args to now be ["-cov=.", "--cov-report", "json"] make sure an json coverage report file is produced