Node.js coverage with GitHub Actions and coveralls

I wanted to automate the coverage of my NPM robots-parser package so all pull requests and commits are checked and coverage is automatically logged. I also wanted to test against multiple versions of node at once.

I’ve used Coveralls in the past, and it’s free for OSS, so I decided to go with that. If you’re using Istanbul/nyc it’s not too difficult to add coveralls support.

By default the Coveralls GitHub will try to load the lcov file from ./coverage/lcov.info which happens to also be the location Istanbul/nyc puts it by default.

So all that’s needed is to add the lcov reporter, which in my case was adding --reporter=lcovonly to the nyc command, and then trigger the coveralls action once it’s run.

The final result:

name: test
on:
  pull_request:
    branches:
      - master
  push:
    branches:
      - master

jobs:
  test:
    runs-on: ubuntu-latest
    timeout-minutes: 5
    strategy:
      matrix:
        node: ["12", "14", "15"]
    name: Node ${{ matrix.node }} test
    steps:
      - uses: actions/checkout@v2
      - name: Setup node
        uses: actions/setup-node@v2
        with:
          node-version: ${{ matrix.node }}
      - run: npm ci
      # Run tests and generate the lcov.info file
      - run: npm test

      # Run the coveralls action which uploads the
      # lcov.info file
      - name: Coveralls Parallel
        uses: coverallsapp/github-action@master
        with:
          github-token: ${{ secrets.github_token }}
          flag-name: run-${{ matrix.node }}
          # This is a parallel build so need this
          parallel: true

  # As testing against multiple versions need this to
  # finish the parallel build
  finish:
    name: Coveralls coverage
    needs: test
    runs-on: ubuntu-latest
    steps:
      - name: Coveralls Finished
        uses: coverallsapp/github-action@master
        with:
          github-token: ${{ secrets.github_token }}
          parallel-finished: true

You can see the YAML file here and what the generated coverage looks like here.

• JavaScript
• GitHub