hoangnguyen0403/flutter-testing

Flutter Testing Standards

Priority: P0 (CRITICAL)

Core Rules

1. Test Pyramid: Unit > Widget > Integration.
2. Naming: should <behavior> when <condition>.
3. AAA: Arrange, Act, Assert in all tests.
4. Shared Mocks: test/shared/ only — no local mocks.
5. File Placement: _integration_test.dart ONLY in integration_test/.
6. Robot-First: ALL UI assertions/interactions via Robot pattern (e.g., CheckoutRobot) — never raw find.*/expect() in test body.

Widget Testing & Mocking

• Setup: Use TestWrapper.init() in setUpAll and tester.pumpLocalizedWidget(...).
• Mocking: Use GetIt registration of Mock BLoCs in setUpAll if created internally. Use blocTest for BLoC logic and whenListen for state transitions.
• Stubbing: Always stub bloc.state and bloc.stream in setUp. Prohibit any() / anyNamed().
• Async: Use settle: false for loading or stream states to verify mid-process transitions.

Robot Pattern

• All interactions and assertions belong in *Robot (e.g., expectFirstOrderVisible()).
• Symmetric: every expectXxxVisible() needs expectXxxNotVisible() pairs.
• BaseRobot Centralization: Extract standard scrolling (scrollDown, scrollToEnd) and screen visibility assertions (expectScreenVisible, expectScreenNotVisible) into common BaseRobot or parent class to avoid duplication.
• Widget tests: include pumpScreen(bloc:, settle:) helper.
• Widget Keys: Use WidgetKeys constants from lib/core/keys/ — never inline Key('string').

Integration Testing

• Use patrolTest with IntegrationAuthHelper.loginOrSkip($) for authenticated flows.
• Use $.native.tap() or $.native.* for native interactions (e.g., system dialogs).
• Create robot: final robot = OrdersRobot($.tester) — share same class as widget tests.
• Only $.native.* and navigation helpers may remain inline in test body.

Anti-Patterns

• No inline Key: Use WidgetKeys constant. No any(): Use typed matchers.
• No local mocks: Use test/shared/. No missing bloc stub: Stub state + stream.
• No test-body logic: Move find.*/expect() to robot. No raw find in integration tests.
• No _integration_test.dart in test/: Rename or merge.
• No unused imports: Remove v_dls when robots handle assertions. Check Material import needs.
• No happy-path-only: Add Edge cases group. No one-sided assertions: Add expectNotVisible pairs.
• No unchecked text casing: Verify .toUpperCase(), .tr() in source.

Verification

• [ ] Fakes used over Mocks for Repositories (well-defined inputs/outputs).
• [ ] Every ViewModel has unit tests covering loading, success, and error states.
• [ ] Every View has widget tests with faked ViewModel.
• [ ] Critical user flows have at least one integration test.
• [ ] flutter test passes.