Visual and Accessibility Testing

A pixel-perfect design that a screen reader cannot parse is broken. A fully accessible page that looks nothing like the mockup is also broken. Visual and accessibility testing are two sides of the same coin: ensuring that what users see and what users experience are both correct.

Why These Disciplines Are Complementary

Visual testing ensures the interface matches the design intent. Accessibility testing ensures the interface works for all users, including those using assistive technology. Together, they guarantee that your application is both correct and inclusive.

AI-powered tools have transformed both fields. Vision models can distinguish meaningful visual changes from rendering noise. AI agents can evaluate whether alt text is descriptive, not just present. This chapter covers the full spectrum from pixel-diff tools to WCAG compliance automation.

Topics Covered

1. Visual Regression — 01-visual-regression/

• AI-Powered Comparison — How vision models compare screenshots and the AI visual testing workflow
• Commercial Tools — Percy, Chromatic, Applitools Eyes with code examples
• Open-Source Tools — Playwright built-in, BackstopJS, reg-suit, Loki, Lost Pixel

2. Accessibility Automation — 02-accessibility-automation/

• WCAG Compliance — Automatable vs manual checks, axe-core integration
• axe-core Integration — Playwright + axe-core, accessibility trees, full-site audits
• ARIA and Contrast — ARIA best practices, color contrast verification
• Keyboard Navigation — Complete keyboard testing, focus traps, modal dialogs

3. Business Case — 03-business-case/

• Legal Landscape — ADA, European Accessibility Act, global regulations
• Market Impact — User base, SEO, brand reputation, and ROI

4. Advanced Testing — 04-advanced-testing/

• AI Accessibility Audits — AI agents crawling applications for qualitative accessibility assessment
• Storybook Testing — Component-level visual and accessibility testing
• Design System Verification — Matching Figma to implementation, design token drift detection

5. Pipeline — 05-pipeline/

• Visual and Accessibility CI — Complete CI/CD pipeline, key takeaways, and interview talking points

Prerequisites

Familiarity with Playwright and basic CI/CD concepts (GitHub Actions or similar). The accessibility sections assume no prior WCAG knowledge -- the chapter builds from fundamentals. For the Storybook sections, basic React component understanding is helpful. Design token verification assumes familiarity with CSS custom properties.