Support GitLab-compatible Cobertura format in MTP natively

[latop2604]

Hello 👋,

I’m currently using GitLab, which supports displaying code coverage information directly inside the diff view of a merge request. It relies on the Cobertura format for this feature.

Previously, when I was using coverlet, this worked perfectly out of the box. However, after switching to Microsoft.Testing.Platform and the Microsoft.Testing.Extensions.CodeCoverage package, the coverage report stopped working in GitLab.

After some experimentation, I was able to make it work again by manually tweaking the generated Cobertura XML file:

dotnet run -c Release -- --report-junit --coverage --coverage-output-format cobertura --coverage-output myapp.cobertura.xml
sed -i "s@filename=\"$CI_PROJECT_DIR/@filename=\"@g" bin/Release/net9.0/TestResults/myapp.cobertura.xml
sed -i "s@<packages>@<sources><source>$CI_PROJECT_DIR/</source></sources><packages>@g" bin/Release/net9.0/TestResults/myapp.cobertura.xml

The idea here is:

• Replace all absolute paths in the nodes with relative paths.
• Add a node containing the base path.

This makes GitLab correctly display coverage information in merge requests.
However, having to run these sed commands after each test run is not ideal.

👉 Question:
Is there already a built-in option or configuration to achieve this behavior natively?
And if not, would it be possible to add support for relative paths and sources in the Cobertura output?

Thanks a lot for your work on this project!

[fhnaseer]

You can try using "DeterministicReport" in the coverage settings file. More details in here https://github.com/microsoft/codecoverage/blob/main/docs/configuration.md

[latop2604]

Thx, but I don't think it will work, as gitlab will not be able to map it anymore to the real file path.

[latop2604]

I tested it using a a testconfig.json file. But did not work.

{
  "codeCoverage": {
    "Configuration": {
      "DeterministicReport": true
    }
  }
}

Is it possible to override /_/ by something I can input somewhere?

[fhnaseer]

No, it is not possible to override this.