Upload junit reports codecov

[aleguy02]

Description

This PR automates uploading JUnit reports to codecov in the test pipeline. An example pipeline run with the changes can be found here (https://github.com/aleguy02/fork-pytest/actions/runs/18184970357). An example of what the codecov UI looks like with these changes can be found here (https://app.codecov.io/gh/aleguy02/fork-pytest/tests).

Closes #12689

Checklist

• Include documentation when adding new features.
• Include new tests or update existing tests when applicable.
• Allow maintainers to push and squash when merging my commits. Please uncheck this if you prefer to squash the commits yourself.

Additional Notes

I didn't create a changelog since the documented behavior of pytest was not modified.

[webknjaz]

It's a great start! I normally avoid adding --junitxml= (even if the path value is empty) to normal/local invocations. Instead, I like adding the entire CLI flag in the CI definition: https://github.com/cherrypy/cheroot/blob/06a6d67e549ccaefe332cd0539c21e1483031071/.github/workflows/ci-cd.yml#L786.

I've made suggestions below. Let's see if that works..

---

As for the change note, sometimes it's a good idea to use the contrib type for such changes.

[aleguy02]

Do you recommend doing this because it is cleaner to have the entire CLI flag in one place instead of splitting it across the workflow and tox.ini file? If so that makes perfect sense (I'm asking for my personal learning) @webknjaz

[webknjaz]

Change notes are supposed to communicate the effect of upgrading since the previous release. They make up a coherent change log document, which is expected to follow consistent writing style and use full sentences and such. They shouldn't generally reference internal implementation details and be higher level and approachable to the end-users.

This is a contrib note, though, so the "end users" are other contributors (and core devs).

Here's a preview of your addition: https://pytest--13778.org.readthedocs.build/en/13778/changelog.html#contributor-facing-changes.

To me, it looks a bit out of place because it doesn't have a full stop in the sentence, nor does the sentence start with a capital letter.

This will probably fit better:

Suggested change

	automated uploading JUnit reports to codecov in the test workflow with codecov GitHub Action
	The test reports are now published to Codecov from GitHub Actions.
	The test statistics is visible `on the web interface
	<https://app.codecov.io/gh/pytest-dev/pytest/tests>`__.
	-- by :user:`aleguy02`

---

P.S. Technically, this PR does not require a change note but since you added it, let's make it more coherent with the rest.

[webknjaz]

Since this produces one file per job that doesn't go anywhere with this name, we can skip making the name dynamic.

Suggested change

	_PYTEST_TOX_POSARGS_JUNIT: --junitxml=junit-${{ matrix.name }}.xml
	_PYTEST_TOX_POSARGS_JUNIT: --junitxml=junit.xml

[webknjaz]

Suggested change

	_PYTEST_TOX_POSARGS_JUNIT: --junitxml=junit-${{ matrix.name }}.xml
	_PYTEST_TOX_POSARGS_JUNIT: --junitxml=junit.xml

[webknjaz]

Suggested change

	files: junit-${{ matrix.name }}.xml
	files: junit.xml

[nicoddemus]

For consistency with the coverage upload step done above this one, let's use ./junit.xml.

[webknjaz]

Do you recommend doing this because it is cleaner to have the entire CLI flag in one place instead of splitting it across the workflow and tox.ini file? If so that makes perfect sense (I'm asking for my personal learning)

Perhaps. But this is more due to the fact that configuration should be where it belongs. If you add a --junitxml= to tox.ini, that configuration will also be picked up in local runs, when the contributors invoke tox on their computers. Setting it only in CI prevents that.

[nicoddemus]

Overall looks good, thanks @aleguy02.

Please see the requested changes by @webknjaz. 👍