# 18. Screenshot Testing (Paparazzi)

meta:
  id: android-production-18
  feature: android-production
  priority: P2
  depends_on: []
  tags: [testing, screenshots, quality]

objective:
- Implement screenshot testing with Paparazzi to catch UI regressions across different screen sizes and themes

deliverables:
- Paparazzi integration
- Screenshot tests for key screens
- CI verification for screenshot changes
- Golden screenshot baseline

steps:
1. Add Paparazzi:
   - Add plugin to build.gradle.kts
   - Configure for library or application module
   - Set up test directory
2. Create screenshot tests:
   - Test LoginScreen in light and dark themes
   - Test DashboardScreen with data
   - Test AlertItem component
   - Test ServiceRow component
   - Test SettingsScreen
   - Test empty states and error states
3. Generate golden screenshots:
   - Run tests to generate baseline screenshots
   - Review and commit baseline images
   - Document generation process
4. Add CI integration:
   - Run screenshot tests on PR
   - Fail on unapproved changes
   - Upload diff images for review
   - Require approval for screenshot changes
5. Test multiple configurations:
   - Light theme
   - Dark theme
   - Different screen widths (phone, tablet)
   - Different font sizes
   - RTL layout (if supporting)
6. Maintain screenshots:
   - Update baseline when UI intentionally changes
   - Document update process in README
   - Review all screenshot changes in PR

tests:
- Visual: Screenshot tests pass with no changes
- Regression: UI change detected and flagged
- Coverage: All key screens have screenshot tests

acceptance_criteria:
- Paparazzi integrated and configured
- Screenshot tests for 10+ key screens/components
- Golden baseline screenshots generated
- Tests cover light and dark themes
- Tests cover phone and tablet sizes
- CI runs screenshot tests and flags changes
- Diff images uploaded for review
- Screenshot changes require explicit approval
- No false positives from font rendering differences
- Documentation for updating baselines

validation:
- Run screenshot tests → all pass (no changes)
- Change button color → test fails with diff image
- Review diff → clearly shows what changed
- Update baseline → tests pass again
- CI → screenshot check green or shows diff

notes:
- Paparazzi runs tests on JVM (fast, no emulator needed)
- Golden images must be committed to repository
- Be careful with font rendering differences across OS
- Consider using Roborazzi for Compose-specific screenshot testing