Write widget tests for search UI accessibility

Import 'package:flutter_test/flutter_test.dart' and enable semantics with ensureSemantics() at the top of each test. Wrap widgets in a ProviderScope (Riverpod) or BlocProvider (BLoC) depending on the state management used by the search UI components. For live region tests, use SemanticsFlag.isLiveRegion on the target semantics node. For touch target tests, retrieve the render object with tester.renderObject(find.byType(YourWidget)) and assert size >= Size(44, 44).

Group tests logically: one group per WCAG criterion covered (e.g., group('1.3.1 Info and Relationships', ...), group('2.5.8 Target Size', ...)). Use setUp() to reduce boilerplate for common widget tree construction. Do not mock platform channels for this task — pure widget tests are sufficient.

Use flutter_test widget testing exclusively (no integration_test package for this task). Each test should call tester.pumpWidget() with the target widget wrapped in a MaterialApp and any required BLoC/Riverpod providers. Use tester.getSemantics() and the SemanticsController to assert tree structure. Use tester.tap() and tester.pump() to simulate interactions.

Assert touch target sizes by checking the RenderBox size of each interactive element via tester.getSize(). Include negative tests: assert that the live region does NOT announce when results have not yet loaded. Use expect(tester.takeException(), isNull) after each interaction to catch unexpected errors. Target 100% statement coverage of the accessibility-specific code paths.