Write widget tests for ExpiryNotificationBanner
epic-certificate-expiry-notifications-user-interface-task-008 — Write Flutter widget tests for the ExpiryNotificationBanner covering both expiring-soon and expired visual states, BLoC state transitions (loading → loaded → acknowledged), banner persistence (does not disappear until correct event), CTA button tap dispatches the expected BLoC event, and accessibility semantics checks confirming the banner is reachable by screen readers.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 5 - 253 tasks
Can start after Tier 4 completes
Implementation Notes
Create a reusable test helper function buildTestWidget(ExpiryNotificationRecord record, {VoidCallback? onRenewTap}) that wraps the banner in MaterialApp + BlocProvider
Focus on structure, labels, button presence, and event dispatch. Use a FakeExpiryNotificationRecord factory (using default values with named param overrides) to make test data setup readable.
Testing Requirements
All tests are widget tests using flutter_test. Use bloc_test's MockBloc to inject controlled BLoC states. Structure tests in groups: group('expiring-soon state', ...), group('expired state', ...), group('BLoC state transitions', ...), group('persistence', ...), group('accessibility', ...). Use testWidgets for each case.
For Semantics checks use tester.getSemantics(find.byType(ExpiryNotificationBanner)) or find semantics by label. Avoid testing internal implementation details — test observable behavior (what is visible to the user and what events are dispatched).
The persistent banner must remain visible across app sessions and only disappear when a specific backend condition is met (renewal or coordinator acknowledgement). If the BLoC state is not properly sourced from the notification record repository on every app launch, the banner may disappear prematurely or fail to reappear after a session restart.
Mitigation & Contingency
Mitigation: Drive the banner's visibility exclusively from a Supabase real-time subscription on the notification records table filtered by mentor_id and acknowledged_at IS NULL. Never persist banner visibility state locally. Write an integration test that restarts the BLoC and verifies the banner reappears from the database source.
Contingency: If real-time subscriptions introduce latency or connection reliability issues in offline-first scenarios, add a local cache flag that is only cleared when the repository confirms the acknowledgement write succeeded, with a cache TTL of 24 hours as a fallback.
The notification detail view must conditionally render coordinator-specific actions based on the authenticated user's role. Incorrect role resolution could expose the 'Acknowledge Lapse' action to peer mentors or hide it from coordinators, breaking the workflow and potentially allowing unauthorised state changes.
Mitigation & Contingency
Mitigation: Source the role check from the existing role_state_manager BLoC that is already authenticated against Supabase role claims. Do not rely on a local flag. The coordinator acknowledgement service backend also validates role server-side, providing defence in depth. Add widget tests that render the detail view with mentor and coordinator role fixtures and assert the presence or absence of coordinator actions.
Contingency: If a role resolution bug is found in production, immediately disable the acknowledge action via a feature flag and patch the role check in a hotfix release. The server-side validation in the coordinator acknowledgement service ensures no actual state change can occur even if the button is incorrectly rendered.