Initial commit

skills/testing/playwright-e2e-automation/workflow/phase-6-regression.md

@@ -0,0 +1,77 @@
+# Phase 6: Regression Detection
+
+**Purpose**: Compare current screenshots against baselines to detect changes
+
+## Steps
+
+### 1. Load baseline images
+
+- Check if baselines exist in screenshots/baselines/
+- If first run, current screenshots become baselines
+- If baselines exist, proceed to comparison
+
+### 2. Perform pixel-level comparison
+
+```typescript
+import { compareScreenshots } from 'playwright-core/lib/utils';
+
+const diff = await compareScreenshots(
+  baselinePath,
+  currentPath,
+  diffPath,
+  { threshold: 0.2 } // 20% difference threshold
+);
+```
+
+### 3. Generate visual diff reports
+
+- Create side-by-side comparison images
+- Highlight changed regions in red
+- Calculate difference percentage
+- Classify changes:
+  - **Expected**: Intentional changes (new features, fixes)
+  - **Suspicious**: Unintended changes requiring review
+  - **Critical**: Major regressions (broken features)
+
+### 4. Update baselines if approved
+
+Ask user: "Accept these changes as new baseline?"
+- If yes, copy current → baselines
+- If no, flag as regressions needing fixes
+
+## Output
+
+Visual regression report with diff images:
+
+```markdown
+## Regression Report
+
+### Changed Screenshots (3)
+
+| Screenshot | Diff % | Classification |
+|------------|--------|----------------|
+| home-page | 5% | Expected |
+| form-page | 25% | Suspicious |
+| mobile-nav | 45% | Critical |
+
+See screenshots/diffs/ for visual comparisons.
+```
+
+## Performance
+
+~1-2 seconds per image pair
+
+## Common Issues
+
+**No baselines exist**
+- Current screenshots become baselines automatically
+- Message: "No baselines found. Current screenshots saved as baselines."
+
+**False positive diffs**
+- Adjust threshold (default 20%)
+- Ignore dynamic content areas
+- Use stable test data
+
+## Transition
+
+Proceed to Phase 7 (Fix Recommendation Generation)