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Testing & Deployment

Learn testing strategies and deployment practices for Node.js applications.

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Unit Testing with Jest

Learn unit testing with Jest for Node.js applications

Content by: Harsh Zankat

Node.js Developer

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Jest Testing Framework

Jest is a popular JavaScript testing framework that provides a complete testing solution for Node.js applications. It includes test runners, assertion libraries, mocking capabilities, and code coverage.

Jest Setup and Configuration

Code Example

// Install Jest
npm install --save-dev jest

// package.json
{
  "scripts": {
    "test": "jest",
    "test:watch": "jest --watch",
    "test:coverage": "jest --coverage"
  },
  "jest": {
    "testEnvironment": "node",
    "collectCoverageFrom": [
      "src/**/*.js",
      "!src/**/*.test.js"
    ],
    "coverageThreshold": {
      "global": {
        "branches": 80,
        "functions": 80,
        "lines": 80,
        "statements": 80
      }
    }
  }
}

// Basic test example
// src/utils/calculator.test.js
const { add, subtract, multiply, divide } = require('./calculator');

describe('Calculator', () => {
  test('should add two numbers correctly', () => {
    expect(add(2, 3)).toBe(5);
    expect(add(-1, 1)).toBe(0);
  });

  test('should subtract two numbers correctly', () => {
    expect(subtract(5, 3)).toBe(2);
    expect(subtract(0, 5)).toBe(-5);
  });

  test('should handle division by zero', () => {
    expect(() => divide(5, 0)).toThrow('Division by zero');
  });
});

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// Install Jest
npm install --save-dev jest

// package.json
{
  "scripts": {
    "test": "jest",
    "test:watch": "jest --watch",
    "test:coverage": "jest --coverage"
  },
  "jest": {
    "testEnvironment": "node",
    "collectCoverageFrom": [
      "src/**/*.js",
      "!src/**/*.test.js"
    ],
    "coverageThreshold": {
      "global": {
        "branches": 80,
        "functions": 80,
        "lines": 80,
        "statements": 80
      }
    }
  }
}

// Basic test example
// src/utils/calculator.test.js
const { add, subtract, multiply, divide } = require('./calculator');

describe('Calculator', () => {
  test('should add two numbers correctly', () => {
    expect(add(2, 3)).toBe(5);
    expect(add(-1, 1)).toBe(0);
  });

  test('should subtract two numbers correctly', () => {
    expect(subtract(5, 3)).toBe(2);
    expect(subtract(0, 5)).toBe(-5);
  });

  test('should handle division by zero', () => {
    expect(() => divide(5, 0)).toThrow('Division by zero');
  });
});

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Integration Testing

Learn integration testing for Node.js applications

Content by: Prakash Patel

Node.js Developer

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Integration Testing Concepts

Integration testing verifies that different parts of your application work together correctly. It tests the interaction between modules, databases, APIs, and external services.

API Integration Testing

Code Example

// Install testing dependencies
npm install --save-dev supertest jest

// test/integration/api.test.js
const request = require('supertest');
const app = require('../../app');
const User = require('../../models/User');

describe('User API Integration Tests', () => {
  beforeEach(async () => {
    // Clean database before each test
    await User.deleteMany({});
  });

  test('POST /api/users should create a new user', async () => {
    const userData = {
      name: 'John Doe',
      email: 'john@example.com',
      password: 'password123'
    };

    const response = await request(app)
      .post('/api/users')
      .send(userData)
      .expect(201);

    expect(response.body.success).toBe(true);
    expect(response.body.data.name).toBe(userData.name);
    expect(response.body.data.email).toBe(userData.email);
  });

  test('GET /api/users should return all users', async () => {
    // Create test users
    await User.create([
      { name: 'User 1', email: 'user1@example.com', password: 'password' },
      { name: 'User 2', email: 'user2@example.com', password: 'password' }
    ]);

    const response = await request(app)
      .get('/api/users')
      .expect(200);

    expect(response.body.success).toBe(true);
    expect(response.body.data).toHaveLength(2);
  });

  test('PUT /api/users/:id should update user', async () => {
    const user = await User.create({
      name: 'Original Name',
      email: 'original@example.com',
      password: 'password'
    });

    const updateData = { name: 'Updated Name' };

    const response = await request(app)
      .put(`/api/users/${user._id}`)
      .send(updateData)
      .expect(200);

    expect(response.body.data.name).toBe(updateData.name);
  });
});

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// Install testing dependencies
npm install --save-dev supertest jest

// test/integration/api.test.js
const request = require('supertest');
const app = require('../../app');
const User = require('../../models/User');

describe('User API Integration Tests', () => {
  beforeEach(async () => {
    // Clean database before each test
    await User.deleteMany({});
  });

  test('POST /api/users should create a new user', async () => {
    const userData = {
      name: 'John Doe',
      email: 'john@example.com',
      password: 'password123'
    };

    const response = await request(app)
      .post('/api/users')
      .send(userData)
      .expect(201);

    expect(response.body.success).toBe(true);
    expect(response.body.data.name).toBe(userData.name);
    expect(response.body.data.email).toBe(userData.email);
  });

  test('GET /api/users should return all users', async () => {
    // Create test users
    await User.create([
      { name: 'User 1', email: 'user1@example.com', password: 'password' },
      { name: 'User 2', email: 'user2@example.com', password: 'password' }
    ]);

    const response = await request(app)
      .get('/api/users')
      .expect(200);

    expect(response.body.success).toBe(true);
    expect(response.body.data).toHaveLength(2);
  });

  test('PUT /api/users/:id should update user', async () => {
    const user = await User.create({
      name: 'Original Name',
      email: 'original@example.com',
      password: 'password'
    });

    const updateData = { name: 'Updated Name' };

    const response = await request(app)
      .put(`/api/users/${user._id}`)
      .send(updateData)
      .expect(200);

    expect(response.body.data.name).toBe(updateData.name);
  });
});

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Docker Containerization

Learn to containerize Node.js applications using Docker

Content by: Sachin Patel

Node.js Developer

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Docker Basics

Docker is a platform for developing, shipping, and running applications in containers. It provides a consistent environment across different machines and makes deployment easier.

Dockerfile for Node.js

Code Example

# Use official Node.js runtime as base image
FROM node:18-alpine

# Set working directory
WORKDIR /app

# Copy package files
COPY package*.json ./

# Install dependencies
RUN npm ci --only=production

# Copy application code
COPY . .

# Create non-root user
RUN addgroup -g 1001 -S nodejs
RUN adduser -S nextjs -u 1001

# Change ownership
RUN chown -R nextjs:nodejs /app
USER nextjs

# Expose port
EXPOSE 3000

# Health check
HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
  CMD curl -f http://localhost:3000/health || exit 1

# Start application
CMD ["npm", "start"]

# Docker Compose example
# docker-compose.yml
version: '3.8'
services:
  app:
    build: .
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=production
      - MONGODB_URI=mongodb://mongo:27017/myapp
    depends_on:
      - mongo
    restart: unless-stopped

  mongo:
    image: mongo:5.0
    ports:
      - "27017:27017"
    volumes:
      - mongo_data:/data/db
    restart: unless-stopped

volumes:
  mongo_data:

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# Use official Node.js runtime as base image
FROM node:18-alpine

# Set working directory
WORKDIR /app

# Copy package files
COPY package*.json ./

# Install dependencies
RUN npm ci --only=production

# Copy application code
COPY . .

# Create non-root user
RUN addgroup -g 1001 -S nodejs
RUN adduser -S nextjs -u 1001

# Change ownership
RUN chown -R nextjs:nodejs /app
USER nextjs

# Expose port
EXPOSE 3000

# Health check
HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
  CMD curl -f http://localhost:3000/health || exit 1

# Start application
CMD ["npm", "start"]

# Docker Compose example
# docker-compose.yml
version: '3.8'
services:
  app:
    build: .
    ports:
      - "3000:3000"
    environment:
      - NODE_ENV=production
      - MONGODB_URI=mongodb://mongo:27017/myapp
    depends_on:
      - mongo
    restart: unless-stopped

  mongo:
    image: mongo:5.0
    ports:
      - "27017:27017"
    volumes:
      - mongo_data:/data/db
    restart: unless-stopped

volumes:
  mongo_data:

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Cloud Deployment

Learn to deploy Node.js applications to cloud platforms

Content by: Harsh Zankat

Node.js Developer

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Cloud Deployment Strategies

Cloud deployment involves hosting your Node.js application on cloud platforms like AWS, Google Cloud, or Azure. This includes container orchestration, load balancing, and auto-scaling.

AWS Deployment with ECS

Code Example

# Deploy to AWS ECS using Docker
# 1. Build and push Docker image
docker build -t my-nodejs-app .
docker tag my-nodejs-app:latest 123456789.dkr.ecr.us-east-1.amazonaws.com/my-nodejs-app:latest
docker push 123456789.dkr.ecr.us-east-1.amazonaws.com/my-nodejs-app:latest

# 2. Create ECS task definition
{
  "family": "my-nodejs-app",
  "networkMode": "awsvpc",
  "requiresCompatibilities": ["FARGATE"],
  "cpu": "256",
  "memory": "512",
  "executionRoleArn": "arn:aws:iam::123456789:role/ecsTaskExecutionRole",
  "containerDefinitions": [
    {
      "name": "my-nodejs-app",
      "image": "123456789.dkr.ecr.us-east-1.amazonaws.com/my-nodejs-app:latest",
      "portMappings": [
        {
          "containerPort": 3000,
          "protocol": "tcp"
        }
      ],
      "environment": [
        {
          "name": "NODE_ENV",
          "value": "production"
        }
      ],
      "logConfiguration": {
        "logDriver": "awslogs",
        "options": {
          "awslogs-group": "/ecs/my-nodejs-app",
          "awslogs-region": "us-east-1",
          "awslogs-stream-prefix": "ecs"
        }
      }
    }
  ]
}

# 3. Deploy using AWS CLI
aws ecs create-service \
  --cluster my-cluster \
  --service-name my-nodejs-app \
  --task-definition my-nodejs-app:1 \
  --desired-count 2 \
  --launch-type FARGATE \
  --network-configuration "awsvpcConfiguration={subnets=[subnet-12345],securityGroups=[sg-12345],assignPublicIp=ENABLED}"

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# Deploy to AWS ECS using Docker
# 1. Build and push Docker image
docker build -t my-nodejs-app .
docker tag my-nodejs-app:latest 123456789.dkr.ecr.us-east-1.amazonaws.com/my-nodejs-app:latest
docker push 123456789.dkr.ecr.us-east-1.amazonaws.com/my-nodejs-app:latest

# 2. Create ECS task definition
{
  "family": "my-nodejs-app",
  "networkMode": "awsvpc",
  "requiresCompatibilities": ["FARGATE"],
  "cpu": "256",
  "memory": "512",
  "executionRoleArn": "arn:aws:iam::123456789:role/ecsTaskExecutionRole",
  "containerDefinitions": [
    {
      "name": "my-nodejs-app",
      "image": "123456789.dkr.ecr.us-east-1.amazonaws.com/my-nodejs-app:latest",
      "portMappings": [
        {
          "containerPort": 3000,
          "protocol": "tcp"
        }
      ],
      "environment": [
        {
          "name": "NODE_ENV",
          "value": "production"
        }
      ],
      "logConfiguration": {
        "logDriver": "awslogs",
        "options": {
          "awslogs-group": "/ecs/my-nodejs-app",
          "awslogs-region": "us-east-1",
          "awslogs-stream-prefix": "ecs"
        }
      }
    }
  ]
}

# 3. Deploy using AWS CLI
aws ecs create-service \
  --cluster my-cluster \
  --service-name my-nodejs-app \
  --task-definition my-nodejs-app:1 \
  --desired-count 2 \
  --launch-type FARGATE \
  --network-configuration "awsvpcConfiguration={subnets=[subnet-12345],securityGroups=[sg-12345],assignPublicIp=ENABLED}"

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Module 6: Testing & Deployment

Testing & Deployment

Select Topics Overview

Unit Testing with Jest

Integration Testing

Docker Containerization

Cloud Deployment

Unit Testing with Jest

Integration Testing

Docker Containerization

Cloud Deployment

Unit Testing with Jest

Jest Testing Framework

Jest Setup and Configuration

🎯 Practice Exercise

Integration Testing

Integration Testing Concepts

API Integration Testing

🎯 Practice Exercise

Docker Containerization

Docker Basics

Dockerfile for Node.js

🎯 Practice Exercise

Cloud Deployment

Cloud Deployment Strategies

AWS Deployment with ECS

🎯 Practice Exercise

Module 5: API Development & Documentation

Module 7: Real-time Applications

Ready for the Next Module?