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In this tutorial, you’ll clone, configure, and run a Node.js REST API locally before integrating it into a GitHub Actions workflow. By the end, you’ll have a working Express/Mongoose application, a full test suite, and coverage reports.

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Prerequisites

Ensure you have Node.js and npm installed. On Ubuntu/Debian: 
sudo apt update
sudo apt install nodejs npm
Verify your installations:
node -v
npm -v

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1. Clone the Repository

Fetch the source code from GitLab and navigate into the project folder: 
git clone https://gitlab.com/sidd-harth/solar-system
cd solar-system

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2. Install Dependencies

Install all production and development packages defined in package.json: 
npm install

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3. Review package.json

Open package.json to understand scripts, coverage settings, and dependencies.

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Scripts Overview

ScriptDescriptionCommand
startLaunch the Express servernpm start
testRun Mocha tests with JUnit reporternpm test
coverageGenerate coverage reports (LCOV, Cobertura, text)npm run coverage

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NYC Coverage Configuration

"nyc": {
  "check-coverage": true,
  "lines": 90,
  "reporter": ["text", "json-summary"]
}

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Dependencies

PackagePurpose
expressWeb framework
mongooseMongoDB ODM
corsCross-Origin Resource Sharing
mocha-junit-reporterJUnit test reporting
nycCoverage tool

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Dev Dependencies

PackagePurpose
mochaTest framework
chaiAssertion library
chai-httpHTTP integration testing

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4. Application Entry Point (app.js)

This file initializes Express, connects to MongoDB via Mongoose, and defines your REST API endpoints. 
// app.js
const express = require("express");
const bodyParser = require("body-parser");
const path = require("path");
const cors = require("cors");
const mongoose = require("mongoose");

const app = express();
app.use(bodyParser.json());
app.use(express.static(path.join(__dirname, "/")));
app.use(cors());

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("MongoDB connection error:", err);
  } else {
    console.log("MongoDB connected");
  }
});

// Define Mongoose schemas & API routes here...

module.exports = app;
Never commit real credentials. Use environment variables or a secrets manager.

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5. Test Suite (app-test.js)

Uses Mocha, Chai, and Chai HTTP to validate your API endpoints. 
// app-test.js
const server = require("./app");
const chai = require("chai");
const chaiHttp = require("chai-http");

chai.should();
chai.use(chaiHttp);

describe("Planets API Suite", () => {
  describe("GET /planets/:id", () => {
    it("fetches a planet named Mercury", done => {
      chai
        .request(server)
        .get("/planets/1")
        .end((err, res) => {
          res.should.have.status(200);
          res.body.name.should.equal("Mercury");
          done();
        });
    });

    // Add more test cases as needed...
  });
});

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6. Client Logic (client.js)

A simple front-end script that fetches all planets on page load: 
// client.js
console.log("Initializing client.js");

window.onload = () => {
  console.log("Fetching all planets...");
  fetch("/planets")
    .then(res => {
      if (!res.ok) throw new Error("Network response was not ok");
      return res.json();
    })
    .then(data => console.log(data))
    .catch(err => console.error(err));
};

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7. Dockerfile

Containerize the application for consistent deployment: 
FROM node:18-alpine3.17
WORKDIR /usr/app
COPY package*.json ./
RUN npm install
COPY . .
ENV MONGO_URI=uriPlaceholder
ENV MONGO_USERNAME=usernamePlaceholder
ENV MONGO_PASSWORD=passwordPlaceholder
EXPOSE 3000
CMD ["npm", "start"]

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8. Kubernetes Service Manifest

Expose the application via a NodePort service: 
apiVersion: v1
kind: Service
metadata:
  name: solar-system
  namespace: {_NAMESPACE_}
  labels:
    app: solar-system
spec:
  type: NodePort
  selector:
    app: solar-system
  ports:
    - protocol: TCP
      port: 3000
      targetPort: 3000

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9. Running Tests Locally

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9.1 Without Environment Variables

npm test
You’ll encounter: 
MongooseError: The `uri` parameter to `openUri()` must be a string, got `undefined`.

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9.2 Temporary Hard-Coding (Demo Only)

Replace the mongoose.connect call in app.js: 
mongoose.connect("mongodb+srv://supercluster.d83jj.mongodb.net/superData", {
  user: "superuser",
  pass: "SuperPassword",
  useNewUrlParser: true,
  useUnifiedTopology: true
}, err => {
  if (err) console.error("error!!", err);
});
Then: 
npm test
echo $?
Expected output: 
Server successfully running on port - 3000
0
A test_results.xml file will be created for CI consumption.

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10. Generating Coverage Reports

npm run coverage
echo $?
If coverage falls below the 90% threshold, you’ll see: 
ERROR: Coverage for lines (88.88%) does not meet global threshold (90%)
| File   | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
|--------|---------|----------|---------|---------|-------------------|
| All    | 88.88   | 50       | 87.5    | 88.88   | 21,47-48,56       |
Coverage artifacts are saved under coverage/, including:
  • cobertura-coverage.xml
  • coverage-summary.json
  • lcov report

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11. Start the Application

Run the server locally: 
npm start
Visit http://localhost:3000 in your browser. Use the search bar to query planets by ID.
The image shows a webpage with a space-themed background, featuring a "Solar System" search interface and information about Earth.
Tip: Search “3” for Earth or “6” for Saturn.
The image shows a webpage about the solar system, featuring an illustration of Saturn with its rings and a description of the planet. There is a search bar labeled "Search the Planet" and a title "Solar System" at the top.
You’re now prepared to integrate this setup into your GitHub Actions workflow for CI/CD automation.

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References

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