unit-testing-standards

Unit Testing Standards

APPLY: "Write my tests" queries

Testing Philosophy

Based on Adobe AEM unit testing best practices and community discussions:

Testing Framework Stack

• JUnit 5: Primary testing framework
• Mockito: Mock object creation and verification
• wcm.io AEM Mocks: Mock AEM context and services
• Apache Sling Mocks: Mock Sling abstractions

Test Structure Patterns

1. Standard Test File Organization

// ✅ REQUIRED: 1-to-1 mapping with source files
src/main/js/features/hero-marquee/hero-marquee.js
→ test/unit/features/hero-marquee/hero-marquee.test.js

// ✅ REQUIRED: Test suffix naming convention
// Allows easy identification and differentiation from source

2. Basic Test Structure

// ✅ STANDARD: Test structure pattern
describe('Hero Marquee Block', () => {
  let mockEl;
  
  beforeEach(() => {
    // Setup fresh DOM for each test
    document.body.innerHTML = '<div class="hero-marquee"></div>';
    mockEl = document.querySelector('.hero-marquee');
  });
  
  afterEach(() => {
    // Clean up DOM after each test
    document.body.innerHTML = '';
  });
  
  it('should create basic structure', () => {
    // Test the building blocks of functionality
    init(mockEl);
    expect(mockEl.querySelector('.foreground')).to.exist;
  });
  
  it('should handle missing content gracefully', () => {
    // Test edge cases and error conditions
    const emptyEl = document.createElement('div');
    init(emptyEl);
    expect(emptyEl.children.length).to.be.greaterThan(0);
  });
});

3. Testing Asynchronous Block Initialization

// ✅ REQUIRED: Test async block patterns
describe('Async Block Features', () => {
  it('should handle Promise.all data loading', async () => {
    const mockData = { cards: [], ratings: {} };
    
    // Mock async functions
    global.fetchCards = () => Promise.resolve(mockData.cards);
    global.fetchRatings = () => Promise.resolve(mockData.ratings);
    
    await init(mockEl);
    
    // Verify structure is created immediately (LCP optimization)
    expect(mockEl.querySelector('.headline')).to.exist;
    
    // Verify data enhancement happens after
    expect(mockEl.querySelector('.cards-container')).to.exist;
  });
  
  it('should not block LCP with API failures', async () => {
    // Mock API failure
    global.fetchCards = () => Promise.reject(new Error('API Error'));
    
    await init(mockEl);
    
    // Basic structure should still exist
    expect(mockEl.querySelector('.headline')).to.exist;
  });
});