majiayu000 EDS Block Testing Guide
Purpose
Guide developers through testing Adobe Edge Delivery Services (EDS) blocks using test.html files, the development server, and proper EDS integration patterns.
When to Use This Skill
Automatically activates when:
- Creating or editing
test.htmlfiles in block directories - Working with keywords: "test block", "test.html", "debug block"
- Implementing block testing patterns
- Using the development server
Quick Start: Create a Test File
Every block should have a test.html file in its directory:
blocks/your-block/
├── your-block.js
├── your-block.css
├── README.md
├── EXAMPLE.md
└── test.html ← Create this file
Standard Test File Template
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Your Block Test - EDS Native Pattern</title>
<!-- EDS Core Styles -->
<link rel="stylesheet" href="/styles/styles.css">
<link rel="stylesheet" href="/styles/fonts.css">
<link rel="stylesheet" href="/styles/lazy-styles.css">
<!-- Note: Block CSS is loaded automatically by EDS -->
<style>
/* Test-specific styling */
body {
padding: 2rem;
background: var(--light-color);
}
.test-content {
max-width: 1200px;
margin: 0 auto;
background: var(--background-color);
padding: 2rem;
border-radius: 8px;
}
.test-section {
margin: 2rem 0;
padding: 1rem;
border: 1px solid var(--dark-color);
border-radius: 4px;
}
/* EDS pattern - ensure body appears */
body.appear {
display: block;
}
</style>
</head>
<body>
<div class="test-content">
<h1>Your Block Test Page</h1>
<div class="test-section">
<h2>Test Case 1: Basic Usage</h2>
<!-- Your block with test content (note: only block name class, .block is added by script) -->
<div class="your-block">
<div>
<div>Title 1</div>
<div>Description 1</div>
</div>
<div>
<div>Title 2</div>
<div>Description 2</div>
</div>
</div>
</div>
<div class="test-section">
<h2>Test Case 2: With Images</h2>
<div class="your-block">
<div>
<div>
<picture>
<img src="/images/test-image.jpg" alt="Test">
</picture>
</div>
<div>Content with image</div>
</div>
</div>
</div>
</div>
<!-- EDS Core Scripts -->
<script type="module">
import {
sampleRUM,
loadBlock,
loadCSS
} from '/scripts/aem.js';
// Initialize RUM (optional for testing)
sampleRUM('top');
window.addEventListener('load', () => sampleRUM('load'));
// CRITICAL: Add body.appear class FIRST (before loadBlock)
// EDS global styles hide body by default to prevent FOUC
// This makes the page visible before blocks load
document.body.classList.add('appear');
// Load all blocks on the page
// Mimic EDS behavior: find by block name, add .block class automatically
const blocks = document.querySelectorAll('.your-block');
for (const block of blocks) {
try {
// Add .block class like EDS decorateBlock() does
block.classList.add('block');
await loadBlock(block);
console.log(`✅ Block loaded: ${block.className}`);
} catch (error) {
console.error(`❌ Block failed: ${block.className}`, error);
}
}
</script>
</body>
</html>
Important Notes:
- The
document.body.classList.add('appear')line is required and must be called beforeloadBlock(). EDS hides the body by default (body { display: none; }instyles/styles.css) to prevent Flash of Unstyled Content (FOUC). Adding theappearclass makes the page visible. In production, EDS adds this automatically, but test files must add it manually. - The
.blockclass is automatically added by the script (lineblock.classList.add('block')) to mimic EDS production behavior. In your HTML, only use the block name class (e.g.,class="your-block"). - This approach ensures test files behave identically to production where EDS's
decorateBlock()adds the.blockclass automatically.
Development Server Workflow
Start the Server
npm run debug
The server starts on http://localhost:3000 with:
- Automatic proxy fallback to production site
- CORS headers for cross-origin requests
- Enhanced logging for debugging
- Hot-reload support
Access Your Test
http://localhost:3000/blocks/your-block/test.html
Development Flow
- Edit your block JavaScript or CSS
- Refresh the test page in your browser
- Check the browser console for errors
- Iterate and test
EDS Block Structure in Test Files
Basic Two-Column Structure
<div class="your-block">
<!-- Row 1 -->
<div>
<div>Column 1 Content</div>
<div>Column 2 Content</div>
</div>
<!-- Row 2 -->
<div>
<div>Column 1 Content</div>
<div>Column 2 Content</div>
</div>
</div>
Important:
- This structure matches how EDS creates blocks from Google Docs tables
- The
.blockclass is automatically added by EDS'sdecorateBlock()function in production - For test files, you can either:
- Add
.blockmanually:<div class="your-block block"> - Let your test script add it automatically (recommended - mimics production behavior)
- Add
With Images
<div class="your-block">
<div>
<div>
<picture>
<source type="image/webp" srcset="/image.webp">
<img src="/image.jpg" alt="Description" loading="lazy">
</picture>
</div>
<div>Text content</div>
</div>
</div>
With Links
<div class="your-block">
<div>
<div>
<a href="https://example.com">Link Text</a>
</div>
<div>Description</div>
</div>
</div>
With Data Attributes
<div class="your-block"
data-layout="grid"
data-columns="3"
data-autoplay="true">
<!-- Block content -->
</div>
Note: Examples show blocks without the .block class. Your test script should add it automatically to mimic EDS production behavior.
Loading Blocks Programmatically
Basic Block Loading
<script type="module">
import { loadBlock } from '/scripts/aem.js';
const block = document.querySelector('.your-block');
await loadBlock(block);
</script>
Loading Multiple Blocks
<script type="module">
import { loadBlock } from '/scripts/aem.js';
const blocks = document.querySelectorAll('.block');
// Load blocks sequentially
for (const block of blocks) {
await loadBlock(block);
}
// Or load in parallel
await Promise.all(
Array.from(blocks).map(block => loadBlock(block))
);
</script>
With Error Handling
<script type="module">
import { loadBlock } from '/scripts/aem.js';
const blocks = document.querySelectorAll('.block');
for (const block of blocks) {
try {
await loadBlock(block);
console.log(`✅ Loaded: ${block.className}`);
} catch (error) {
console.error(`❌ Failed to load: ${block.className}`, error);
block.innerHTML = '<p class="error">Failed to load block</p>';
}
}
</script>
Testing Different Scenarios
Test Empty Content
<div class="test-section">
<h2>Test Case: Empty Content</h2>
<div class="your-block block">
<!-- No content - test error handling -->
</div>
</div>
Test Invalid Content
<div class="test-section">
<h2>Test Case: Invalid Structure</h2>
<div class="your-block block">
<div>
<div>Only One Column</div>
<!-- Missing second column -->
</div>
</div>
</div>
Test Edge Cases
<div class="test-section">
<h2>Test Case: Very Long Content</h2>
<div class="your-block block">
<div>
<div>Short title</div>
<div>Lorem ipsum dolor sit amet, consectetur adipiscing elit... (very long text)</div>
</div>
</div>
</div>
Test Responsive Behavior
<style>
.test-mobile {
max-width: 375px;
margin: 0 auto;
}
.test-tablet {
max-width: 768px;
margin: 0 auto;
}
</style>
<div class="test-section test-mobile">
<h2>Test Case: Mobile View (375px)</h2>
<div class="your-block block">
<!-- Content -->
</div>
</div>
<div class="test-section test-tablet">
<h2>Test Case: Tablet View (768px)</h2>
<div class="your-block block">
<!-- Content -->
</div>
</div>
Debugging Tips
Console Logging
<script type="module">
import { loadBlock } from '/scripts/aem.js';
const block = document.querySelector('.your-block');
console.group('Block Loading');
console.log('Block element:', block);
console.log('Block classes:', block.className);
console.log('Block content before:', block.innerHTML);
await loadBlock(block);
console.log('Block content after:', block.innerHTML);
console.groupEnd();
</script>
Timing Performance
<script type="module">
import { loadBlock } from '/scripts/aem.js';
const block = document.querySelector('.your-block');
console.time('Block Load Time');
await loadBlock(block);
console.timeEnd('Block Load Time');
</script>
Check Network Requests
Open Chrome DevTools → Network tab to see:
- Which CSS files are loaded
- Which JavaScript modules are loaded
- Any failed requests (404, 500, etc.)
Common Issues and Solutions
Issue: Page is Blank or Invisible
Symptoms:
- Page loads but nothing displays
- Browser shows white/blank screen
- Console shows no JavaScript errors
- Elements exist in DOM but aren't visible
Root Cause: CSS class name conflicts with EDS reserved names
Solution: Never use these class patterns in your CSS or JavaScript:
.{blockname}-container- EDS adds to parent<section>elements.{blockname}-wrapper- EDS adds to block parent<div>wrappers.block- EDS adds to all block elements (avoid styling globally).section- EDS adds to all sections (avoid styling globally).button-container- EDS adds to button parent elements.default-content-wrapper- EDS adds to default content wrappers
Example of the bug:
/* ❌ BAD - Will be applied to parent section, not your modal */
.overlay-container {
position: fixed;
z-index: 999;
opacity: 0; /* Makes entire page invisible! */
}
/* ✅ GOOD - Use different suffix */
.overlay-backdrop {
position: fixed;
z-index: 999;
opacity: 0; /* Only affects your backdrop element */
}
Why this happens:
- EDS's
decorateBlock()adds.{blockname}-containerto parent sections (aem.js:684) - Your CSS targets
.{blockname}-containerfor your component - Browser applies your styles to the section instead of your element
- Section gets
position: fixed; opacity: 0making page invisible
Other global classes that can cause issues:
/* ❌ DANGER - These affect ALL blocks/sections if styled incorrectly */
.block { position: fixed; } /* Breaks ALL blocks */
.section { display: none; } /* Hides ALL sections */
.button-container { overflow: hidden; } /* Breaks ALL buttons */
How to debug:
- Open browser console
- Run:
document.querySelector('section').className - If you see
{blockname}-containerin the class list, rename your CSS classes - Check if styling global classes like
.blockor.sectionwith layout properties
Issue: Block CSS Not Loading
Solution: Ensure your CSS file has the exact same name as your JS file:
blocks/your-block/
├── your-block.js ✅ Matches
├── your-block.css ✅ Matches
└── test.html
Issue: Block Not Rendering
Check:
- Console for JavaScript errors
- Block structure matches expected pattern
decoratefunction is exported as default- Block class name is correct
Issue: Images Not Loading
Solution: Use absolute paths from project root:
<!-- ❌ BAD -->
<img src="image.jpg">
<!-- ✅ GOOD -->
<img src="/images/image.jpg">
Interactive Testing Tools
Add Test Controls
<div class="test-controls">
<button Block</button>
<button Block</button>
<button State</button>
</div>
<script type="module">
import { loadBlock } from '/scripts/aem.js';
const block = document.querySelector('.your-block');
window.reloadBlock = async () => {
console.log('Reloading block...');
block.innerHTML = originalHTML; // Save original
await loadBlock(block);
};
window.clearBlock = () => {
block.innerHTML = '';
};
window.logBlockState = () => {
console.log('Block state:', {
className: block.className,
children: block.children.length,
innerHTML: block.innerHTML
});
};
// Save original HTML
const originalHTML = block.innerHTML;
await loadBlock(block);
</script>
Data Attribute Testing
<div class="test-controls">
<label>
Layout:
<select
<option value="grid">Grid</option>
<option value="list">List</option>
<option value="carousel">Carousel</option>
</select>
</label>
</div>
<div class="your-block block" data-layout="grid">
<!-- Content -->
</div>
<script type="module">
import { loadBlock } from '/scripts/aem.js';
const block = document.querySelector('.your-block');
const originalHTML = block.innerHTML;
window.updateLayout = async (layout) => {
block.innerHTML = originalHTML;
block.dataset.layout = layout;
await loadBlock(block);
};
await loadBlock(block);
</script>
Accessibility Testing
Test Keyboard Navigation
<div class="test-section">
<h2>Accessibility Test</h2>
<p>Use Tab to navigate, Enter/Space to activate</p>
<div class="your-block block">
<!-- Interactive content -->
</div>
</div>
<script type="module">
// Log keyboard events for testing
document.addEventListener('keydown', (e) => {
console.log('Key pressed:', e.key, 'on:', e.target);
});
</script>
Test Screen Reader Compatibility
Use Chrome DevTools:
- Open DevTools → Elements
- Right-click element → Inspect Accessibility Properties
- Check ARIA labels, roles, and descriptions
Performance Testing
Measure Rendering Time
<script type="module">
import { loadBlock } from '/scripts/aem.js';
const block = document.querySelector('.your-block');
// Mark start time
performance.mark('block-load-start');
await loadBlock(block);
// Mark end time
performance.mark('block-load-end');
// Measure duration
performance.measure(
'block-load-time',
'block-load-start',
'block-load-end'
);
const measure = performance.getEntriesByName('block-load-time')[0];
console.log(`Block loaded in ${measure.duration.toFixed(2)}ms`);
</script>
Check for Memory Leaks
<script type="module">
import { loadBlock } from '/scripts/aem.js';
const block = document.querySelector('.your-block');
// Load and unload multiple times
for (let i = 0; i < 100; i++) {
const originalHTML = block.innerHTML;
await loadBlock(block);
// Reset for next iteration
block.innerHTML = originalHTML;
}
console.log('Memory test complete - check DevTools Memory tab');
</script>
Related Documentation
- EDS Block Development - Block development patterns
- EDS Native Testing Standards - Comprehensive testing guide
- Debug Guide - Debugging workflows
- Development Server - Server configuration
Testing Checklist
Before considering your block complete, test:
- Basic functionality with standard content
- Empty/missing content handling
- Very long content (text overflow)
- Images load correctly
- Links work and have correct targets
- Responsive behavior (mobile, tablet, desktop)
- Keyboard navigation
- Screen reader compatibility
- Performance (load time < 100ms for simple blocks)
- Browser console shows no errors
- Works with multiple instances on same page
Next Steps
- Create test.html for your block
- Start the development server:
npm run debug - Access your test file in the browser
- Test all scenarios and edge cases
- Fix any issues found during testing
- Document test results in your README.md
Remember: Proper testing ensures your block works correctly in all scenarios and provides a great user experience on the production site!