Unit tests for BiometricAuthService and Bloc
epic-biometric-session-authentication-core-services-task-010 — Write unit tests covering all BiometricAuthService methods and BiometricAuthBloc state transitions. Tests cover: device capability detection on both platforms, all outcome branches (success, failure, cancel, lockout, fallback), offline mode deferred network behavior, step-up auth gating, and Bloc state machine transitions. Uses flutter_test with mocked LocalAuthIntegration and SupabaseSessionManager.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 7 - 84 tasks
Can start after Tier 6 completes
Implementation Notes
Use mocktail over mockito to avoid code generation overhead in a test-only task. Structure tests in three files: biometric_auth_service_test.dart (service logic), biometric_auth_bloc_test.dart (state machine), and biometric_auth_integration_mock_test.dart (composed flows). For Bloc tests, prefer blocTest() from package:bloc_test over manual stream assertions — it handles async event dispatch and teardown cleanly. For offline deferred behavior, inject a connectivity notifier mock that exposes a StreamController
For lockout, verify that the Bloc emits BiometricLockedOut state and that a subsequent authenticate() event while locked out immediately re-emits the lockout state without calling LocalAuthentication. Document each test group with a brief comment explaining the scenario being modelled. Ensure test fixtures are defined as constants at the top of each file to avoid magic strings.
Testing Requirements
This task IS the testing task. Specifically: (1) Unit tests using flutter_test — no widget or integration tests required here. (2) Use bloc_test's blocTest() helper to assert exact state sequences emitted by BiometricAuthBloc. (3) Use fake_async to control Timer behavior for lockout recovery and offline retry logic without real delays.
(4) Each test class must call setUp() to initialize fresh mocks and tearDown() to dispose streams/blocs. (5) Test naming convention: 'given_[context]_when_[action]_then_[expected]'. (6) Generate coverage report with flutter test --coverage; coverage/lcov.info must show ≥95% line coverage on BiometricAuthService and BiometricAuthBloc.
Multiple concurrent callers (e.g., SessionResumeManager and a background sync service) could simultaneously detect a near-expired token and each invoke SupabaseSessionManager.refreshSession(), causing duplicate refresh API calls and potentially a token invalidation race condition on the Supabase Auth server. This can result in one caller receiving a valid refreshed token while another receives a 401, causing intermittent authentication failures.
Mitigation & Contingency
Mitigation: Implement a single-flight pattern inside SupabaseSessionManager so that concurrent refresh calls coalesce into one in-flight request. Use a Dart Completer or AsyncMemoizer to ensure all waiters receive the same refreshed token. Write a concurrent integration test to validate the single-flight behaviour.
Contingency: If the single-flight pattern introduces deadlocks or timeout complexity, fall back to a mutex-based lock with a 10-second timeout, logging a warning if the lock is held longer than expected, and triggering a full re-login if the refresh ultimately fails.
Supabase Row-Level Security policies evaluate the JWT claims (user_id, role, org_id) on every query. If the refreshed token contains stale or changed claims — for example if a coordinator's role was updated server-side — RLS may silently block data access even though the session appears valid from the client's perspective, causing confusing empty screens rather than an authentication error.
Mitigation & Contingency
Mitigation: After every token refresh, decode the new JWT and compare key claims (role, org_id) with the cached values. If claims have changed, emit a session-claims-changed event that triggers a role re-resolution and navigation reset. Document this behaviour in the SupabaseSessionManager API contract.
Contingency: If claims drift is detected in production and causes data visibility issues, provide a force-refresh mechanism in the UI (pull-to-refresh on home screen) that clears cached role state and re-fetches from Supabase, accompanied by a user-visible toast indicating the session was refreshed.
Allowing session resumption from cached local token when offline introduces a window where a revoked or invalidated session can still grant app access. For example, if a coordinator deactivates a peer mentor's account while the mentor is offline, the mentor continues to have access until connectivity is restored and the token is validated server-side.
Mitigation & Contingency
Mitigation: Set a maximum offline grace period (e.g., 24 hours) stored alongside the token in SecureSessionStorage. If the grace period is exceeded, force a full credential re-login regardless of connectivity status. Scope offline access to read-only operations only, requiring connectivity for any write that reaches Supabase.
Contingency: If the offline grace period logic is found to be insufficient for compliance, implement remote session invalidation via a lightweight push notification that clears SecureSessionStorage even when the app is backgrounded, using FCM with a data-only message.