Upload test coverage report in human-readable HTML format

[desrosj]

The Test Coverage workflow currently generates a coverage report XML file using --coverage-clover and uploads that to Codecov for consumption and display.

The coverage workflow only runs currently on every commit, but only some PRs scoped to specific related files being updated. There are some situations where a human-readable format, like HTML, would be very useful.

As an example, I updated the workflow to produce HTML coverage reports for comparing the impact of the change in [57566].

The HTML report could just be uploaded to the workflow as an artifact.

Trac ticket: https://core.trac.wordpress.org/ticket/60476

[jorbin]

Love this.

[desrosj]

In 57570:

Build/Test Tools: Generate a human-readable HTML coverage report.

This updates the test coverage GitHub Actions workflow to generate a human-readable HTML report in addition to the current machine readable one submitted to Codecov.

Props jorbin.
Fixes #60476.

Merged in https://core.trac.wordpress.org/changeset/57570.

[swissspidy]

What's the advantage of the HTML report over looking at the coverage change on Codecov?

[desrosj]

Because of how long the workflow takes (30-40 minutes), we don't currently run it on every push or pull request unless certain configuration files are changed/updated.

But on pull requests, the reports are never pushed to Codecov. In my case, I was changing the version of PHP used to generate the report and needed to compare the outcome to make sure it would not result in a sizable drop in overall coverage. I wasn't able to easily check because the report was XML, and not uploaded anywhere.

From time to time, I consider submitting reports for all PRs. But there's reasonable arguments for both sides and I usually just decide it's better to save the time and resources.