Advanced visual regression testing with pixel-perfect comparison, AI-powered diff analysis, responsive design validation, and cross-browser visual consistency. Use when detecting UI regressions, validating designs, or ensuring visual consistency.
Installation
Details
Usage
After installing, this skill will be available to your AI coding assistant.
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skills listSkill Instructions
name: visual-testing-advanced description: "Advanced visual regression testing with pixel-perfect comparison, AI-powered diff analysis, responsive design validation, and cross-browser visual consistency. Use when detecting UI regressions, validating designs, or ensuring visual consistency." category: specialized-testing priority: high tokenEstimate: 900 agents: [qe-visual-tester, qe-test-executor, qe-quality-gate] implementation_status: optimized optimization_version: 1.0 last_optimized: 2025-12-02 dependencies: [] quick_reference_card: true tags: [visual, regression, screenshot, pixel-diff, percy, playwright, responsive]
Advanced Visual Testing
<default_to_action> When detecting visual regressions or validating UI:
- CAPTURE baseline screenshots (first run establishes baseline)
- COMPARE new screenshots against baseline (pixel-by-pixel or AI)
- MASK dynamic content (timestamps, ads, user counts)
- TEST across devices (desktop, tablet, mobile viewports)
- REVIEW and approve intentional changes, fail on regressions
Quick Visual Testing Steps:
- Set up baseline on main branch
- Compare feature branch against baseline
- Mask dynamic elements (timestamps, avatars)
- Use AI-powered comparison to reduce false positives
- Integrate in CI/CD to block visual regressions
Critical Success Factors:
- Functional tests don't catch visual bugs
- AI-powered tools reduce false positives
- Review diffs, don't just auto-approve </default_to_action>
Quick Reference Card
When to Use
- UI component changes
- CSS/styling modifications
- Responsive design validation
- Cross-browser consistency checks
Visual Bug Types
| Bug Type | Description |
|---|---|
| Layout shift | Elements moved position |
| Color change | Unintended color modification |
| Font rendering | Typography issues |
| Alignment | Spacing/alignment problems |
| Missing images | Broken image paths |
| Overflow | Content clipping |
Comparison Algorithms
| Algorithm | Best For |
|---|---|
| Pixel diff | Exact match requirement |
| Structural similarity | Handle anti-aliasing |
| AI semantic | Ignore insignificant changes |
Visual Regression with Playwright
import { test, expect } from '@playwright/test';
test('homepage visual regression', async ({ page }) => {
await page.goto('https://example.com');
// Capture and compare screenshot
await expect(page).toHaveScreenshot('homepage.png');
// First run: saves baseline
// Subsequent runs: compares to baseline
});
test('responsive design', async ({ page }) => {
// Mobile viewport
await page.setViewportSize({ width: 375, height: 667 });
await page.goto('https://example.com');
await expect(page).toHaveScreenshot('homepage-mobile.png');
// Tablet viewport
await page.setViewportSize({ width: 768, height: 1024 });
await expect(page).toHaveScreenshot('homepage-tablet.png');
});
Handling Dynamic Content
test('mask dynamic elements', async ({ page }) => {
await page.goto('https://example.com');
await expect(page).toHaveScreenshot({
mask: [
page.locator('.timestamp'), // Dynamic time
page.locator('.user-count'), // Live counter
page.locator('.advertisement'), // Ads
page.locator('.avatar') // User avatars
]
});
});
AI-Powered Visual Testing (Percy)
import percySnapshot from '@percy/playwright';
test('AI-powered visual test', async ({ page }) => {
await page.goto('https://example.com');
// Percy uses AI to ignore anti-aliasing, minor font differences
await percySnapshot(page, 'Homepage');
});
test('component visual test', async ({ page }) => {
await page.goto('https://example.com/components');
// Snapshot specific component
const button = page.locator('.primary-button');
await percySnapshot(page, 'Primary Button', {
scope: button
});
});
Playwright Configuration
// playwright.config.js
export default {
expect: {
toHaveScreenshot: {
maxDiffPixels: 100, // Allow 100 pixel difference
maxDiffPixelRatio: 0.01, // Or 1% of image
threshold: 0.2, // Color similarity threshold
animations: 'disabled', // Disable animations
caret: 'hide' // Hide cursor
}
}
};
Agent-Driven Visual Testing
// Comprehensive visual regression
await Task("Visual Regression Suite", {
baseline: 'main-branch',
current: 'feature-branch',
pages: ['homepage', 'product', 'checkout'],
devices: ['desktop', 'tablet', 'mobile'],
browsers: ['chrome', 'firefox', 'safari'],
threshold: 0.01
}, "qe-visual-tester");
// Returns:
// {
// comparisons: 27, // 3 pages × 3 devices × 3 browsers
// differences: 2,
// report: 'visual-regression-report.html'
// }
Agent Coordination Hints
Memory Namespace
aqe/visual-testing/
├── baselines/* - Baseline screenshots
├── comparisons/* - Diff results
├── components/* - Component snapshots
└── reports/* - Visual regression reports
Fleet Coordination
const visualFleet = await FleetManager.coordinate({
strategy: 'visual-testing',
agents: [
'qe-visual-tester', // Screenshot comparison
'qe-test-executor', // Cross-browser execution
'qe-quality-gate' // Block on visual regressions
],
topology: 'parallel'
});
Related Skills
- accessibility-testing - Visual a11y checks
- compatibility-testing - Cross-browser visuals
- regression-testing - Regression suite
Remember
Functional tests don't catch visual bugs. Layout shifts, color changes, font rendering, alignment issues - all invisible to functional tests but visible to users.
AI-powered tools reduce false positives. Percy, Applitools use AI to ignore insignificant differences (anti-aliasing, minor font rendering).
With Agents: qe-visual-tester automates visual regression across browsers and devices, uses AI to filter noise, and generates visual diff reports. Catches UI regressions before users see them.
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