Quality Engineering at Scale: Unit Tests, Cypress, Git Hooks & SonarCloud Integration

// PaymentProcessor.test.js - Comprehensive unit testing example
import PaymentProcessor from '../PaymentProcessor';
import { mockPaymentGateway, mockAuditLogger } from '../__mocks__';

describe('PaymentProcessor', () => {
  let paymentProcessor;
  let mockGateway;
  let mockLogger;

  beforeEach(() => {
    mockGateway = mockPaymentGateway();
    mockLogger = mockAuditLogger();
    paymentProcessor = new PaymentProcessor(mockGateway, mockLogger);
  });

  describe('processPayment', () => {
    it('should successfully process a valid payment', async () => {
      // Arrange
      const paymentRequest = {
        amount: 99.99,
        currency: 'AUD',
        cardToken: 'tok_1234567890',
        customerId: 'cus_test123'
      };
      
      mockGateway.charge.mockResolvedValue({
        id: 'charge_test123',
        status: 'succeeded',
        amount: 9999
      });

      // Act
      const result = await paymentProcessor.processPayment(paymentRequest);

      // Assert
      expect(result.success).toBe(true);
      expect(result.chargeId).toBe('charge_test123');
      expect(mockLogger.logPaymentSuccess).toHaveBeenCalled();
    });

    it('should handle payment failures gracefully', async () => {
      mockGateway.charge.mockRejectedValue({
        type: 'card_error',
        code: 'card_declined'
      });

      const result = await paymentProcessor.processPayment({
        amount: 50.00,
        currency: 'AUD'
      });

      expect(result.success).toBe(false);
      expect(result.error.type).toBe('card_error');
    });
  });
});

// cypress/e2e/checkout-flow.cy.js
describe('E-commerce Checkout Flow', () => {
  beforeEach(() => {
    cy.task('db:seed');
    cy.intercept('POST', '/api/payments/process', {
      fixture: 'payment-success.json'
    }).as('processPayment');
  });

  it('completes full purchase journey', () => {
    cy.visit('/products/wireless-headphones');
    cy.get('[data-testid="add-to-cart-btn"]').click();
    cy.get('[data-testid="checkout-btn"]').click();

    // Fill shipping information
    cy.get('input[name="email"]').type('test@example.com');
    cy.get('input[name="address"]').type('123 Test Street');
    
    // Fill payment information
    cy.get('input[name="cardNumber"]').type('4242424242424242');
    cy.get('input[name="expiryDate"]').type('12/25');
    
    cy.get('[data-testid="complete-purchase-btn"]').click();
    cy.wait('@processPayment');
    
    cy.url().should('include', '/order-confirmation');
    cy.get('[data-testid="order-confirmation"]')
      .should('contain', 'Order Confirmed');
  });
});

# .husky/pre-commit
#!/usr/bin/env sh
echo "🔍 Running pre-commit checks..."

# Lint staged files
npx lint-staged

# Type checking
npx tsc --noEmit

# Security audit
npm audit --audit-level moderate

echo "✅ Pre-commit checks completed!"

# package.json scripts
{
  "scripts": {
    "test:unit": "jest --testPathPattern=__tests__/unit",
    "test:integration": "jest --testPathPattern=__tests__/integration",
    "test:e2e": "cypress run",
    "lint": "eslint . --ext .js,.jsx,.ts,.tsx --fix",
    "prepare": "husky install"
  }
}

# lint-staged.config.js
module.exports = {
  '*.{js,jsx,ts,tsx}': [
    'eslint --fix',
    'prettier --write',
    'jest --findRelatedTests --passWithNoTests'
  ]
};

# sonar-project.properties
sonar.projectKey=quality-engineering-example
sonar.organization=handy-hasan
sonar.sources=src
sonar.tests=src
sonar.test.inclusions=**/*.test.js,**/*.spec.js
sonar.javascript.lcov.reportPaths=coverage/lcov.info

# GitHub Actions Quality Pipeline
name: Quality Analysis
on: [push, pull_request]
jobs:
  quality:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Setup Node.js
        uses: actions/setup-node@v3
        with:
          node-version: '18'
      - name: Install dependencies
        run: npm ci
      - name: Run tests with coverage
        run: npm run test:coverage
      - name: SonarCloud Scan
        uses: SonarSource/sonarcloud-github-action@master
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}