Skip to main content
In this guide, we’ll configure GitLab CI/CD for the Solar System NodeJS project and add a robust unit testing job. You’ll learn how to create a structured .gitlab-ci.yml, manage sensitive MongoDB credentials via CI/CD variables, and ensure your NodeJS tests run reliably.

​
1. Initialize GitLab CI/CD Configuration

Start by creating a new file named .gitlab-ci.yml at your repository root. Define the pipeline stages and add a placeholder build job: 
stages:
  # Define the execution order of pipeline stages
  - build
  - test
  - deploy

build-job:
  stage: build
  script:
    - echo "Building the project..."
Explicit stages improve readability and make it easier to extend the pipeline with additional jobs.

​
2. Define Workflow Rules

Specify when the pipeline should trigger by adding a workflow section with conditional rules: 
workflow:
  name: Solar System NodeJS Pipeline
  rules:
    # Run on pushes to main or feature branches
    - if: $CI_COMMIT_BRANCH == "main" || $CI_COMMIT_BRANCH =~ /^feature/
      when: always
    # Run on merge request events from feature branches
    - if: $CI_MERGE_REQUEST_SOURCE_BRANCH_NAME =~ /^feature/ && $CI_PIPELINE_SOURCE == "merge_request_event"
      when: always

stages:
  - test

​
3. Add the Unit Testing Job

Next, define the unit_testing job in the test stage. This job uses the official NodeJS Docker image, installs dependencies, and runs tests with Mocha: 
unit_testing:
  stage: test
  image: node:17-alpine3.14
  before_script:
    - npm install
  script:
    - npm test
Commit these changes to a new feature branch: 
git checkout -b feature/setup-gitlab-ci
git add .gitlab-ci.yml
git commit -m "chore: add GitLab CI/CD pipeline with unit testing"
git push -u origin feature/setup-gitlab-ci
Pushing to feature/* will trigger a pipeline run.
The image shows a GitLab CI/CD pipeline interface for a project named "Solar System NodeJS Pipeline," indicating a failed unit testing job. The sidebar includes options for managing the project, such as issues, merge requests, and pipelines.

​
4. Diagnose the Test Failure

Inspect the job logs. The runner pulls the NodeJS image and installs packages, but npm test fails with a Mongoose connection error. Our application code in app.js relies on environment variables: 
const mongoose = require('mongoose');

mongoose.connect(process.env.MONGO_URI, {
  user: process.env.MONGO_USERNAME,
  pass: process.env.MONGO_PASSWORD,
  useNewUrlParser: true,
  useUnifiedTopology: true,
}, err => {
  if (err) {
    console.error("Connection error:", err);
  } else {
    console.log("MongoDB Connection Successful");
  }
});
Without the MongoDB credentials, tests cannot connect.

​
5. Supply Environment Variables

Add a variables section at the top of your .gitlab-ci.yml to inject the connection details: 
variables:
  MONGO_URI: 'mongodb+srv://supercluster.d83jj.mongodb.net/superData'
  MONGO_USERNAME: superuser
  MONGO_PASSWORD: $M_DB_PASSWORD

stages:
  - test

unit_testing:
  stage: test
  image: node:17-alpine3.14
  before_script:
    - npm install
  script:
    - npm test
Never expose plain-text passwords in your repository. Always use masked CI/CD variables for credentials.
Here’s a quick reference for these variables:
Variable NamePurposeExample
MONGO_URIMongoDB connection stringmongodb+srv://.../superData
MONGO_USERNAMEDatabase user namesuperuser
MONGO_PASSWORDMasked variable reference$M_DB_PASSWORD

​
6. Configure Masked Variables in GitLab

In your GitLab project, navigate to Settings > CI/CD > Variables. Create a new variable:
  • Key: M_DB_PASSWORD
  • Value: (your database password)
  • Masked: ✔
  • Protected: as required
The image shows a GitLab CI/CD settings page, specifically focusing on the section for managing variables. It includes details about a masked variable named "M_DB_PASSWORD" and a notification confirming its successful addition.
Return to the Pipeline Editor on your feature branch and commit the updated .gitlab-ci.yml:
The image shows a GitLab Pipeline Editor interface with options to switch branches and configure a CI/CD pipeline. The sidebar includes various project management options like Merge requests, Manage, Plan, and more.

​
7. Verify the Successful Pipeline

A new pipeline should start automatically. This time, the unit_testing job completes successfully:
The image shows a GitLab CI/CD pipeline interface for a project named "Solar System NodeJS Pipeline," indicating a successful test job labeled "unittesting." The pipeline has passed, and the interface displays various project management options on the left sidebar.

​
8. Review the Test Logs

The job log confirms the install and test steps: 
$ npm install
added 364 packages, and audited 365 packages in 8s
44 packages are looking for funding
Run `npm fund` for details
vulnerabilities (1 high, 1 critical)
To address all issues, run:
  npm audit fix

$ npm test
> Solar [email protected] test
> mocha app-test.js --timeout 10000 --reporter mocha-junit-reporter --exit
Server successfully running on port 3000
  ✓ should return all planets
  ✓ should return planet by ID
  ...
Now that unit tests are passing, the next step is to collect test reports using the artifacts keyword.

​
References

Watch Video