Run Code Coverage Job using a Container and Service

In this guide, you’ll learn how to set up a code coverage workflow in GitHub Actions by combining a job container with a MongoDB service container. This approach ensures all steps run in a consistent environment and can connect to your database service seamlessly.

1. Recap: Unit Testing with a Service Container

Below is a sample job that runs unit tests in Node.js while using a MongoDB service container:

jobs:
  unit-testing:
    name: Unit Testing
    runs-on: ${{ matrix.operating_system }}
    services:
      mongo-db:
        image: siddharth67/mongo-db:non-prod
        ports:
          - 27017:27017
        env:
          MONGO_URI: "mongodb://localhost:27017/superData"
          MONGO_USERNAME: non-prod-user
          MONGO_PASSWORD: non-prod-password
    strategy:
      matrix:
        nodejs_version: [18, 20]
        operating_system: [ubuntu-latest]
        exclude:
          - nodejs_version: 18
            operating_system: macos-latest
    steps:
      - uses: actions/checkout@v4
        name: Checkout Repository

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

      - uses: actions/cache@v3
        name: Cache npm Dependencies
        with:
          path: node_modules
          key: ${{ runner.os }}-node-modules-${{ hashFiles('package-lock.json') }}

      - run: npm install
        name: Install Dependencies

      - run: npm test
        id: nodejs-unit-testing-step
        name: Run Unit Tests

      - if: always()
        uses: actions/upload-artifact@v3
        name: Archive Test Results
        with:
          name: Mocha-Test-Result
          path: test-results.xml

Service Name	Image	Ports	Environment Variables
mongo-db	siddharth67/mongo-db:non-prod	27017:27017	`MONGO_URI`, `MONGO_USERNAME`, `MONGO_PASSWORD`

2. What Is a Job Container?

A job container allows you to execute every step of a job inside a specified Docker image instead of on the default runner VM. This ensures your CI environment matches production more closely.

The image shows a GitHub Docs page about "Running jobs in a container" using GitHub Actions, with an overview and example YAML code.

(See: https://docs.github.com/en/actions/using-jobs/running-jobs-in-a-container)

jobs:
  example-job:
    runs-on: ubuntu-latest
    container:
      image: node:18
    steps:
      - name: Verify Docker Environment
        run: |
          if [ -f ./dockerenv ]; then
            echo "Found dockerenv"
          else
            echo "No dockerenv"
          fi

By specifying container.image, all subsequent steps run inside that Docker image. You no longer need a separate setup action for Node.js.

3. Defining the Code Coverage Workflow

The following workflow runs a code coverage job in a Node.js 18 container and attaches a MongoDB service container for database operations:

name: CI
on:
  push:
    branches: [ main ]

jobs:
  code-coverage:
    name: Code Coverage
    runs-on: ubuntu-latest
    container:
      image: node:18
    services:
      mongo-db:
        image: siddharth67/mongo-db:non-prod
        options: --name mongo
    env:
      MONGO_URI: 'mongodb://mongo:27017/superData'
      MONGO_USERNAME: non-prod-user
      MONGO_PASSWORD: non-prod-password

    steps:
      - uses: actions/checkout@v4
        name: Checkout Repository

      - uses: actions/cache@v3
        name: Cache npm Dependencies
        with:
          path: node_modules
          key: ${{ runner.os }}-node-modules-${{ hashFiles('package-lock.json') }}

      - run: npm install
        name: Install Dependencies

      - run: npm run coverage
        name: Run Code Coverage

Key Point	Details
Job Container Image	`node:18`
Service Container	`siddharth67/mongo-db:non-prod`
Service Network Alias	`mongo` (used in `MONGO_URI`)
No `setup-node` Step Needed	Node is preinstalled within the job container image

Make sure the service container name (mongo) matches the hostname used in MONGO_URI. Incorrect naming can lead to connection failures.

4. Verify and Inspect Logs

After committing and pushing your workflow, navigate to the Actions tab in GitHub. You should see both the Unit Testing and Code Coverage jobs running in parallel.

The image shows a GitHub Actions workflow interface with jobs for unit testing and code coverage in progress. It includes a visual representation of the workflow steps and their status.

The image shows a GitHub Actions workflow interface with a list of jobs and steps for code coverage, indicating successful completion of tasks like setting up a job, initializing containers, and checking out the repository.

In the logs, you’ll find Docker commands demonstrating how GitHub Actions starts both the job and service containers:

/usr/bin/docker start 99621c88b3e11e3a36090a1a87149e466bf5e8479ab5a54185f073369248
/usr/bin/docker create --name mongo --network github_network \
  -e GITHUB_ACTIONS=true -e CI=true sidharth67/mongo-db:non-prod

Introduction

Continuous Integration with GitHub Actions

Continuous Deployment with GitHub Actions

Reusable Workflows and Reporting

Custom Actions

Self Hosted Runner

Security Guide

GitHub Actions - Core Concepts

Run Code Coverage Job using a Container and Service

1. Recap: Unit Testing with a Service Container

2. What Is a Job Container?

3. Defining the Code Coverage Workflow

4. Verify and Inspect Logs

Links and References

Watch Video

​1. Recap: Unit Testing with a Service Container

​2. What Is a Job Container?

​3. Defining the Code Coverage Workflow

​4. Verify and Inspect Logs

​Links and References

Watch Video

1. Recap: Unit Testing with a Service Container

2. What Is a Job Container?

3. Defining the Code Coverage Workflow

4. Verify and Inspect Logs

Links and References