Run and Test NodeJS App on Local Machine

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.

Prerequisites

Ensure you have Node.js and npm installed. On Ubuntu/Debian:

sudo apt update
sudo apt install nodejs npm

node -v
npm -v

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

2. Install Dependencies

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

npm install

3. Review package.json

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

Scripts Overview

NYC Coverage Configuration

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

Dependencies

Dev Dependencies

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;

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...
  });
});

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));
};

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"]

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

9. Running Tests Locally

9.1 Without Environment Variables

npm test

You’ll encounter:

MongooseError: The `uri` parameter to `openUri()` must be a string, got `undefined`.

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.

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

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.

Tip: Search “3” for Earth or “6” for Saturn.

You’re now prepared to integrate this setup into your GitHub Actions workflow for CI/CD automation.

References

• Express.js Documentation
• Mongoose Docs
• MongoDB Official Site
• Kubernetes Services
• Docker Hub