Add test coverage

[rbarman]

Description

Add test coverage (#181)

The .github/workflows/python-tests.yml workflow now:

• Creates test coverage report with pytest-cov
• Creates a comment in PR with test coverage info
• Uploads coverage info to Codecov
• See this PR on my fork as an example of what happens: Test PR with coverage comment and codecov rbarman/itscalledsoccer#6 (comment)

Also updated CONTRIBUTING.md with steps on how to locally generate the test coverage report.

Checklist

• Code compiles correctly
• Created tests which fail without the change (if applicable)
• All lint and unit tests passing
• Extended the README / documentation, if necessary

Additional Comments

Repo owners will need to enable this repo with Codecov and set the CODECOV_TOKEN as a repository secret.

[rbarman]

Hi @bgrnwd , the pipeline fails at the "Pytest coverage comment" step when it tries to comment on this PR.

Error: HttpError: Resource not accessible by integration
Error: Resource not accessible by integration

But it is successful on my fork - https://github.com/rbarman/itscalledsoccer/actions/runs/9917117549/job/27400194105

I'm skimming through some other threads like actions/labeler#12 and it looks like the issue is that PRs from forks have read only access to the main repo and thus it can't create the coverage comment.

Might have to do more research, but some possible options that come to mind:

• Remove the action step that creates a comment. The PR approver will need to go to Codecov to review code coverage.
• Update this repo settings for forks to have more access. (Not really ideal for security issues)
• Give people permissions to create branches directly on this repo. (Also not ideal)

[bgrnwd]

@rbarman Just saw your comment. I think the first option is the way to go for now and we can add a Code Cov badge to the README.

[rbarman]

Alright, I need to create another commit to go with option 1

[rbarman]

@bgrnwd , thanks for merging. Just as a reminder, you or the repo owners will need to enable this repo with Codecov and set the CODECOV_TOKEN as a repository secret. You go to repo settings -> "Secrets and variables" -> "Actions" -> "New Repository Secret"

Because I just checked the github action runs for this PR (https://github.com/American-Soccer-Analysis/itscalledsoccer/actions/runs/9967409315/job/27541042634#step:7:34) and see:

Error: Codecov token not found. Please provide Codecov token with -t flag.

[bgrnwd]

Looks like we already have a CODECOV_TOKEN set up from a couple years ago so I'll investigate that error a little more