Integration test: end-to-end preview and diff flow
epic-bufdir-report-preview-screen-and-diff-task-013 — Write an integration test that drives the full coordinator flow from period selection through preview to export: navigate to BufdirPreviewScreen with a seeded session, verify validation banner appears with correct warnings, open the diff panel, confirm prior-period data loads and threshold-exceeded rows are highlighted, dismiss the diff panel, tap Export and confirm the warning dialog appears, acknowledge the dialog and verify navigation to export screen with correct session state.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 7 - 84 tasks
Can start after Tier 6 completes
Implementation Notes
Seed data should include: (1) a BufdirReportSession row with status='draft', a known period_id, and at least 3 fields with validationState='warning' and 1 with validationState='anomaly'; (2) a prior-period snapshot row with at least one field exceeding the configured threshold percentage so the diff highlight logic is exercised. Use a custom FlutterDriver or IntegrationTestWidgetsFlutterBinding. Wrap the entire screen under test in a ProviderScope/BlocProvider with real Supabase client pointed at the test project. If BufdirPreviewService uses Riverpod, override the provider with ProviderContainer in the test harness.
For the diff panel highlight assertion, read the BoxDecoration color from the widget tree using tester.widget
Testing Requirements
This IS the integration test. Use the flutter integration_test package (not flutter_test unit tests). Seed data via Supabase client in setUpAll. Structure the test as a single sequential testWidgets call covering the entire user journey to avoid ordering issues.
Use pumpAndSettle with a timeout after each async action. Assert widget states via Finder + expect(find.byKey(...), findsOneWidget). Add a separate short unit test file verifying the session state object equality after dialog acknowledgement using a mock navigator observer. Target: 100% branch coverage of the happy path and the 'user dismisses dialog' cancellation path.
The preview screen must pass period, scope, and aggregation session state to the Bufdir Report Export screen via navigation arguments. If the export screen's navigation argument schema is not yet finalized when this epic begins, the handoff will require rework — potentially after TestFlight is already in use by coordinators.
Mitigation & Contingency
Mitigation: Define the shared BufdirExportNavigationArgs Dart class jointly with the Bufdir Report Export feature team before this epic starts. Store it in a shared models package both features depend on. Treat the class as an API contract with a minor-version bump policy.
Contingency: If the export screen's argument schema changes after the preview screen is implemented, the BufdirPreviewService session state model can be adapted with a compatibility shim. The preview screen itself requires only a one-line navigation call change.
The period diff view loads prior-period data on demand and renders it inline with the current report. On a large report (many sections, many fields) combined with slow Supabase connectivity, the diff overlay could block the UI or produce a janky re-render that degrades the coordinator experience during the pre-submission review.
Mitigation & Contingency
Mitigation: Load prior-period data in a background Riverpod FutureProvider that starts prefetching when the preview screen mounts (not when the user taps the diff toggle). Show a shimmer placeholder on each field row's prior-period column while loading. Cache prior-period data in BufdirPreviewRepository using the same local cache as current-period data.
Contingency: If diff view performance is unacceptable on TestFlight devices, disable the toggle for the initial TestFlight release and ship the diff view in the following sprint after profiling the Supabase query plan and adding an appropriate Postgres index on the prior-period data table.
The full preview screen will be reviewed by coordinators on TestFlight who will cross-reference it against their physical Bufdir reporting forms. Any section ordering difference or label mismatch discovered during UAT will require a fix before the feature can be signed off, potentially delaying the entire Bufdir reporting pipeline.
Mitigation & Contingency
Mitigation: Conduct a pre-TestFlight alignment review with at least one coordinator from NHF and one from HLF using a static screenshot of the preview screen layout. Obtain written sign-off on section order and field labels before distributing to the full test group of 5-8 people.
Contingency: If label mismatches are found during TestFlight UAT, update BufdirReportStructureMapper constants and rebuild. Since the mapper is a pure Dart class with no persisted state, corrections are deployed in the next TestFlight build with no database migration required.