Workflow Configure Code Coverage

In this guide, we’ll enhance an existing GitHub Actions workflow by adding a dedicated code coverage job. The new job runs in parallel with unit tests, generates coverage reports using npm run coverage, and archives the results for later inspection.

Environment Variables

Make sure the following variables are defined in your repository settings:

1. Existing Unit Testing Job

This YAML snippet configures a matrix-based unit testing job across multiple Node.js versions and OS environments:

env:
  MONGO_URI: 'mongodb+srv://supercluster.d83jj.mongodb.net/superData'
  MONGO_USERNAME: ${{ vars.MONGO_USERNAME }}
  MONGO_PASSWORD: ${{ secrets.MONGO_PASSWORD }}

jobs:
  unit-testing:
    name: Unit Testing
    strategy:
      matrix:
        nodejs_version: [18, 19, 20]
        operating_system: [ubuntu-latest, macos-latest]
      exclude:
        - nodejs_version: 18
          operating_system: macos-latest
    runs-on: ${{ matrix.operating_system }}
    steps:
      - name: Checkout Repository
        uses: actions/checkout@v4

      - name: Setup Node.js ${{ matrix.nodejs_version }}
        uses: actions/setup-node@v3
        with:
          node-version: ${{ matrix.nodejs_version }}

      - name: Install Dependencies
        run: npm install

      - name: Run Unit Tests
        run: npm test

      - name: Archive Test Results
        uses: actions/upload-artifact@v3
        with:
          name: Unit-Test-Results
          path: test-results
          retention-days: 5

2. Job Overview

3. Adding the Code Coverage Job

Add a second job named code-coverage right below the existing unit-testing definition:

env:
  MONGO_URI: 'mongodb+srv://supercluster.d83jj.mongodb.net/superData'
  MONGO_USERNAME: ${{ vars.MONGO_USERNAME }}
  MONGO_PASSWORD: ${{ secrets.MONGO_PASSWORD }}

jobs:
  unit-testing: # existing job…

  code-coverage:
    name: Code Coverage
    runs-on: ubuntu-latest
    steps:
      - name: Checkout Repository
        uses: actions/checkout@v4

      - name: Setup Node.js 18
        uses: actions/setup-node@v3
        with:
          node-version: 18

      - name: Install Dependencies
        run: npm install

      - name: Generate Coverage Report
        run: npm run coverage

      - name: Archive Coverage Report
        uses: actions/upload-artifact@v3
        with:
          name: Code-Coverage-Result
          path: coverage
          retention-days: 5

Running npm run coverage outputs coverage data under the coverage folder, which the upload-artifact action then archives for 5 days.

4. Viewing Artifacts in the GitHub Actions UI

Artifacts from each workflow run appear in the Artifacts section of the run summary. You can remove individual artifacts manually or rely on the retention-days setting for automatic cleanup.

5. Handling Coverage Threshold Failures

ERROR: Coverage for lines (88.88%) does not meet global threshold (90%)
File       | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
-----------|---------|----------|---------|---------|-------------------
All files  |   88.88 |      50  |   87.5  |   88.88 | 21, 47-48, 56
app.js     |   88.88 |      50  |   87.5  |   88.88 | 21, 47-48, 56
Error: Process completed with exit code 1.

6. Next Steps

• Write additional tests to boost coverage above your threshold.
• Tweak or disable the coverage threshold in your test config.
• Implement error-handling strategies to archive critical artifacts regardless of step failures.

Links and References

• GitHub Actions Documentation
• actions/checkout @ GitHub Marketplace
• actions/setup-node @ GitHub Marketplace
• actions/upload-artifact @ GitHub Marketplace