Report coverage information with --tests

[rcrowe]

Is there an existing issue for this?

• I have searched the existing issues

Feature description

When running --tests also report coverage so that we can enforce tests cover all combinations of policy evaluation.
While CEL can make that evaluation complex, even some basic output that a line is covered or not is helpful.

What would the ideal solution look like to you?

Supplying --coverage alongside --tests where coverage information is then reported in the different output formats.

Ideally, the coverage reports would be SCM change aware; for example, only files that changed in a PR via git diff would have their tests/coverage reported on. That would then allow us to enforce coverage on files changing, but that feels like a feature that would be better as part of --tests & a new feature request. I mention it here so I can describe the usecase we had envisaged for coverage reports.

Alternatively, perhaps the file path is included in the coverage report so we can filter in userland...

{
  "coverage": {
    "some/file/path.yaml": [...]
  }
}

Anything else?

No response