Determines the test coverage of a Python module using coverage.py. Generates a badge for the determined coverage when triggered by a push event. When triggered by a pull_request event, the determined coverage is added as a comment to the corresponding pull request.

Example badge generated using this action:

1. The main workflow should be given an expressive name, such as:

   name: Report test coverage

2. The main workflow should be triggered by push and pull_request events. For push events, make sure that the workflow is only triggered on the main branch, or whichever branch you want to be associated with the value reported by the generated badge:

   on:
     pull_request:
     push:
       branches: ['master']

3. Create a Gist which will be used to store the values for the badge. To do that, simply create an empty Gist. You will need the ID of the Gist. If https://gist.github.com/kostrykin/d152375a04f7ab9ee9b247de41245b24 is the URL of your Gist, then d152375a04f7ab9ee9b247de41245b24 is the ID.
4. Create a PAT with Gist permission, and add it as your GIST_SECRET by going to your repository Settings > Secrets and variables > Actions > New repository secret.
5. Add the action to the workflow and replace d152375a04f7ab9ee9b247de41245b24 by your Gist ID:

   - uses: kostrykin/report-test-coverage-action@v1.1.0
     with:
       gist-id: d152375a04f7ab9ee9b247de41245b24
       gist-auth: ${{ secrets.GIST_SECRET }}

   When embedded into a matrix strategy (e.g., for testing multiple Python versions), the reporting should be restricted to a single step. This can be achieved, for example, by adding:

       report: ${{ strategy.job-index == 0 }}

   You can also specify a working-directory as a relative path to the root of the repository (e.g., ./example) if your Python module and the corresponding tests directory are not direct descendents of the repository root.

For a full example, see the workflow file .github/workflows/test.yml and the example/ directory.

To report the test coverage as comments in pull requests, a second workflow must be set up. This is because the main workflow runs in the context of the base branch of the pull request (which potentially is a fork repository that has no permissions to post comments into the pull request of the upstream repository). The post-comment.yml workflow should look as follows:

name: Post pull request comment

on:
  workflow_run:
    workflows: [Report test coverage]  # Replace this by EXACT NAME of the main workflow!
    types: [completed]

jobs:
  post_pr_comment:
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    if: ${{ github.event.workflow_run.conclusion == 'success' }}
    steps:

      - uses: kostrykin/post-gh-comment-from-artifact-action@v1.0.0
        with:
          github-auth: ${{ secrets.GITHUB_TOKEN }}

List of further examples:

• https://github.com/BMCV/giatools
• https://github.com/BMCV/segmetrics
• https://github.com/kosmotive/cs2pb
• https://github.com/kostrykin/repype
• https://github.com/kostrykin/tournaments