Integration Test: Speech Adapter Lifecycle and Error Recovery

The key challenge in this test suite is correctly mocking the MethodChannel without a real device. Use the pattern: final log = []; channel.setMockMethodCallHandler((call) async { log.add(call); return mockResponses[call.method]; }). For partial transcript streaming, use a StreamController in the mock and advance it step by step within fakeAsync(). The app-background test requires the adapter to implement WidgetsBindingObserver — verify this is done before writing the test, as it is the mechanism for lifecycle detection.

For locale switching, confirm the adapter's contract: does it emit a final partial transcript before restarting, or discard it? Document this behaviour explicitly in a test description string. Important user context: Blindeforbundet and HLF require speech-to-text for post-session report writing (not during sessions) — tests should reflect this: recording is user-initiated post-session, never auto-started.

Integration tests using flutter_test. Use TestWidgetsFlutterBinding and mock the native MethodChannel (e.g., 'com.app/speech') using TestDefaultBinaryMessengerBinding.instance.defaultBinaryMessenger.setMockMethodCallHandler() to intercept platform calls. Use fakeAsync() for timeout and streaming tests to avoid real delays. Use StreamController in the mock bridge to emit partial transcripts in sequence.

For lifecycle tests, call ServicesBinding.instance.handleAppLifecycleStateChanged(AppLifecycleState.paused) to simulate backgrounding. Verify state transitions using expectLater() on the adapter's state stream. All tests grouped by lifecycle phase: 'permissions', 'recording lifecycle', 'streaming', 'locale', 'background', 'error recovery'.