This action looks for a defined clover or cobertura file and parses that to give you feedback not only about current coverage but also coverage against the base a pull request might be merging into. It uses Github's workflow artifacts to store the raw coverage files for later comparison and it generates a markdown file that is appended to the job summary and that can also be used in something like marocchino/sticky-pull-request-comment. (See our workflows for examples)

I couldn't find any action that did comparisons between branches in a pull request (without commiting back to the repository). Plus I like the idea of this being written in typescript which compiles down to javascript since it's supported in all of Github's runner environments

This example will execute when any pull request is made against the branch main or if any code is pushed to the branch main. It then uses marocchino/sticky-pull-request-comment to post a comment with the coverage back to the Pull Request

ci.yml

name: 'ci'
on:
  pull_request:
    branches:
      - main
  push:
    branches:
      - main

jobs:
  ci:
    runs-on: ubuntu-latest
    steps:
      - run: npm run test
      - uses: clearlyip/[email protected]
        id: code_coverage_report_action
        with:
          filename: 'coverage/clover.xml'
          fail_on_negative_difference: true
          artifact_download_workflow_names: 'ci,cron'
      - name: Add Coverage PR Comment
        uses: marocchino/sticky-pull-request-comment@v2
        if: steps.code_coverage_report_action.outputs.file != '' && github.event_name == 'pull_request' && (success() || failure())
        with:
          recreate: true
          path: code-coverage-results.md

cron.yml

name: 'cron'
on:
  workflow_dispatch:
  schedule:
    - cron:  '0 0 1 * *'

jobs:
  cron:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - uses: actions/setup-node@v3
        with:
          node-version: 16
      - run: npm ci
      - run: npm run test
      - uses: clearlyip/[email protected]
        id: code_coverage_report_action
        with:
          filename: 'coverage/clover.xml'

See action.yml

The following outputs are returned from the action. You can utilize these outputs in other steps as long as you set an id against the step that uses this action (see the Default Usage example)

The generated markdown file path

The overall coverage of the project as a percentage

This action uses artifacts to store the coverage files so they can be referenced later for differences when using pull requests. The benefits of this are that you don't have to run any type of hosted server. However Github has retenion limits on artifacts. As a result there are a couple of things you need to know

Github states the following:

• The retention period for artifacts for public repositories is anywhere between 1 day or 90 days.
• The retention period for artifacts for private repositories is between 1 day or 400 days.

As a result of this you will need to setup a job to run that will process your coverage files less than your retention period. Otherwise you wont get diffs when made against branches.

The example below uses two workflow actions. workflow_dispatch which allows you to manually run this workflow and schedule which is set to run monthly (~30 days).

In the job steps we setup our environment and then we run our test suite which generates our coverage file, then we process this file. Since the event name is not pull_request the action simply takes the coverage file and places it inside the artifact

name: 'cron'
on:
  workflow_dispatch:
  schedule:
    - cron:  '0 0 1 * *'

jobs:
  cron:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - uses: actions/setup-node@v3
        with:
          node-version: 16
      - run: npm ci
      - run: npm run test >> "${GITHUB_STEP_SUMMARY}"
      - uses: clearlyip/[email protected]
        with:
          filename: 'coverage/clover.xml'

After this is done you will need to modify any job that uses this action to reference itself and additionally the cron workflow above by name using artifact_download_workflow_names:

      - uses: clearlyip/[email protected]
        id: code_coverage_report_action
        with:
          filename: 'coverage/clover.xml'
          fail_on_negative_difference: true
          artifact_download_workflow_names: 'ci,cron'