[Discussion] Native Dagger integration for pytest-cov test coverage

[mozluk]

Background

Following the discussion in #97, we want to establish test coverage reporting/enforcement across modules shipping pytest suites (github, ruff, uv).

Proposed Direction

Rather than injecting coverage tooling directly into GitHub Actions workflow YAML, the goal is to implement coverage natively within the Dagger pipeline:

• Leverage or open-source the internal Dagger module code integrating with pytest-cov.
• Expose a clean Dagger function (e.g. dagger call test --coverage or a dedicated coverage function) that executes tests with coverage reporting out of the box.
• Allow optional threshold checks without breaking module-level isolation.

Opening this issue as a placeholder to discuss API design and integration details whenever maintainer bandwidth permits.

[danielgafni]

So one of the nice things we have internally is the ability to do test splitting and merging of coverage reports. This is needed quite often. Anyway thanks for the issue and I will get back to you later!

[danielgafni]

Also this might just be an official Dagger module. They have one for pytest so making one for pytest-cov also makes sense.

[mozluk]

An official/ecosystem-level Dagger module for pytest-cov would be fantastic and benefit a lot of teams beyond this workspace.

Do you see this as:

1. Extending the existing Daggerverse pytest module with --cov, splitting, and merge capabilities, or
2. Building a dedicated, standalone pytest-cov module from scratch?

Happy to help scaffold the interface and test runner contract if you have a preferred architecture in mind.