common-web-visual-testing

🌐 Web Visual & Behavioral Testing

Priority: P1 (HIGH)

[!IMPORTANT] Tier 2 (Methodology): Strategy web UI/UX audit. Tier 3 (Domain): Responsive, A11y (WCAG), Browser Engine quirk.

🧪 Testing Mindset (Comparative Audit)

Visual test best as Comparative Audit loop:

Baseline (Before): Capture snapshot --aria + screenshot prod/main.
Implementation (After): Capture same local/feature.
Audit: Compare state for regression, CLS, Aria drift.

Responses must label the two captures as Before and After (or Baseline and Fixed) and include the diff and neighboring-element side-effect check.

📋 Scenario Matrix

Change Type	Scenarios to Run
CSS/Layout	Responsive Audit + Hover + CLS Check
Forms/Input	Validation Msg + Focus State + Error Boundary
Navigation	URL Sync + Sticky Header + Back-Button Persistence
Assets/Fonts	Lazy Load + Icon Check + LCP Audit
Accessibility	Tab Order + Aria-Snapshot + Color Contrast

🚫 Anti-Patterns

Single-Viewport: Never verify Desktop only. Check Mobile (375px) + Tablet (768px).
Ignore Layout Shift: Check loading state (skeleton) → no page jump.
Unmasked Dynamic: MUST mask timestamp/balance via --mask or JS (opacity: 0). Avoid "False Regression".
Blind Assertion: Use playwright-cli snapshot --aria verify state before done.
External Dependency: Mock/bypass 3rd-party (Chat, Analytics) → prevent flakiness.

🔗 References

playwright-cli: playwright-cli
Diagnostic Decoder: diagnostic-decoder
DOM vs Screenshot: dom-snapshot-vs-screenshot
Login & Data: login-and-test-data
Scenario Details: scenarios