testing

Create a testWidgets that pumps the widget via a shared pumpApp helper, then call expectLater with matchesGoldenFile pointing to a goldens/ PNG path. Tag the file or test with a TestTag.golden constant so goldens can run or update independently.

Use package:mocktail, never package:mockito. Declare mocks as private classes like _MockApiClient extends Mock, stub with when/thenAnswer, verify with verify(...).called(n), and register fallback values in setUpAll for custom types used with any().

Use MockBloc or MockCubit from package:bloc_test instead of real blocs, stub the state in setUp, and wrap the widget in BlocProvider.value inside a buildSubject helper. Group tests by behavior categories like renders, navigates, and calls.

pumpAndSettle hangs when infinite animations like CircularProgressIndicator are present, since frames never settle. Use pump() with explicit durations instead, and pass timeout_seconds to the test tool so a hung run is killed.

Run them through the very_good_cli MCP test tool: pass tags: 'golden' to run only goldens, add update_goldens: true to regenerate reference PNGs, or exclude_tags: 'golden' to skip them. Commit the updated PNG files alongside the tests.

Use widget tests for behavioral outcomes like text content, callbacks, and navigation. Use golden tests for visual appearance such as layout, colors, and typography. Never assert padding, color, or font size in a widget test.