Why Test Accessibility?
Think your site is accessible? There's only one way to find out. And spoiler: running a single tool and calling it a day won't cut it. A real accessibility test combines automated tools (which catch about 30-40% of issues) with manual testing (essential for the remaining 60-70% that machines simply can't detect).
Automated Tests
Start with RGAA Test (rgaa-test.fr) for a comprehensive RGAA-specific audit. Add axe DevTools as a browser extension for daily development checks. WAVE is great for beginners because it overlays errors visually on the page -- you can see exactly where things go wrong. Lighthouse in Chrome DevTools gives a quick score, but don't rely on it alone -- it barely scratches the surface.
Manual Tests
Here's a trick I use with every team I train: unplug your mouse. Seriously. Navigate your entire site using only Tab, Shift+Tab, Enter, Space, arrows, and Escape. Is every interactive element reachable? Can you see where focus is? Then fire up a screen reader -- NVDA (free, Windows) or VoiceOver (built into Mac). You'll mess up the first time. That's fine. But you'll learn more in 15 minutes than hours of reading specs. Finally, zoom to 200% and check your contrast ratios.
Quick Checklist
My express checklist covers the essentials: image alt text (criteria 1.1-1.9), contrast ratios (3.2-3.3), keyboard navigation (7.1, 12.7), heading hierarchy (9.1), form labels (11.1-11.2), explicit links (6.1), page language (8.3), page titles (8.5-8.6), and video subtitles (4.1-4.3).
Here's the golden rule: no single tool catches everything. A proper accessibility test always combines automated scanning with manual human checks. They're a package deal.