Unit test ActivityRegistrationCubit state machine
epic-quick-activity-registration-business-logic-task-012 — Write unit tests for ActivityRegistrationCubit using bloc_test. Cover: initialization emits correct pre-filled state, step advancement blocked when required field empty, step advancement succeeds when complete, goBack restores previous state without data loss, submit emits Submitting then Success with optimistic record, submit emits Failure with plain-language message on service error, and last-used type is saved after success. Mock ActivityRegistrationService and RegistrationDefaultsManager.
Acceptance Criteria
Technical Requirements
Execution Context
Tier 5 - 253 tasks
Can start after Tier 4 completes
Implementation Notes
The critical subtlety for the goBack test is ensuring the cubit stores a state history stack internally — verify this is implemented as an immutable list of past states, not a mutable stack. For the initialization test, stub RegistrationDefaultsManager.getDefaults() to return a known defaults object and assert the pre-filled activityType matches. For the submit idempotency case (submitting while already submitting), add a test that calls submitRegistration() twice in act and verifies only one Submitting state is emitted. Use mocktail's any() matcher for arguments when the exact value is not the focus of the test, but use exact matchers when testing the saved activity type ID to catch regressions.
Testing Requirements
Use bloc_test package's blocTest() function for all Cubit tests — do not use manual emit() testing. Each blocTest must specify build, act, expect, and verify sections. Group tests by behavior category (initialization, navigation, submission). Use a shared buildCubit() helper in setUp() to avoid duplication.
For the goBack data-loss test, populate specific field values in act before navigating back and assert those values appear in the restored state. Run flutter test --coverage and confirm 100% branch coverage on the Cubit's state machine logic.
The wizard Cubit manages multiple concurrent state slices (current step, each field value, submission status, error state). As the number of wizard steps grows, the state class can become unwieldy, making it difficult to reason about transitions, leading to subtle bugs where advancing a step resets a previously filled field.
Mitigation & Contingency
Mitigation: Use an immutable state model (copyWith pattern) with a separate sealed class per wizard step state. Keep the Cubit's emit calls minimal and always derive the next state from the current state to prevent accidental field resets. Document the state machine transitions explicitly in code comments.
Contingency: If state complexity becomes unmanageable, split into a parent WizardCubit (owns step navigation and submission) and per-step child Cubits (own individual field state), coordinating via a shared repository layer.
Organisation-specific compensation eligibility rules (e.g., activity type + duration thresholds) are business logic that may change independently of the app release cycle. Hardcoding these rules in ActivityRegistrationService means rule changes require a new app deployment, causing delays and potential financial errors if the deployed version uses outdated rules.
Mitigation & Contingency
Mitigation: Model compensation rules as configuration fetched from Supabase (stored per organisation), cached locally. ActivityRegistrationService reads from cache with a fallback to hardcoded defaults for offline scenarios. Design the rule schema to be extensible without code changes.
Contingency: If dynamic rules are not ready for initial release, ship with hardcoded rules and a feature flag that enables the remote-config path. Document the rule structure clearly so coordinators can trigger a rule update via a Supabase dashboard entry rather than a code deployment.
The last-used activity type stored in RegistrationPreferencesStore may become invalid if the organisation administrator deactivates that activity type between sessions. The Cubit would pre-populate a deleted type, and either the UI would show a missing item or submission would fail with a foreign-key constraint error.
Mitigation & Contingency
Mitigation: In RegistrationDefaultsManager, validate the retrieved last-used activity type ID against the current list of active types fetched from the activity type repository. If the stored ID is not in the active list, fall back to the first active type alphabetically.
Contingency: If validation cannot be performed offline, surface a non-blocking warning in the activity type step ('Your previously used activity type is no longer available') and require the user to make a new selection before advancing.