feat(ground-suite): add replay observability console

ground-suite/test/features/observability/observability_controller_test.dart

@@ -0,0 +1,112 @@
+import 'dart:async';
+
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:ground_suite/core/observations/observed_event.dart';
+import 'package:ground_suite/core/observations/vehicle_data_port.dart';
+import 'package:ground_suite/core/observations/vehicle_data_update.dart';
+import 'package:ground_suite/features/observability/presentation/observability_controller.dart';
+
+void main() {
+  test('coalesces rapid critical accessibility announcements', () async {
+    final port = _ControlledDataPort();
+    final container = ProviderContainer(
+      overrides: [vehicleDataPortProvider.overrideWithValue(port)],
+    );
+    addTearDown(container.dispose);
+
+    container.read(observabilityControllerProvider);
+    await Future<void>.delayed(Duration.zero);
+
+    port.events.add(
+      ObservationReceived(
+        ErrorEvent(
+          receivedAt: DateTime.utc(2026, 8, 10),
+          path: 'kaptan_drivers::lidar_lite_v3::error::Error::TransferFault',
+        ),
+      ),
+    );
+    await Future<void>.delayed(Duration.zero);
+
+    expect(
+      container.read(observabilityControllerProvider).accessibilityAnnouncement,
+      'Error received: kaptan_drivers::lidar_lite_v3::error::Error::TransferFault',
+    );
+
+    port.events.add(
+      ObservationReceived(
+        ShutdownEvent(
+          receivedAt: DateTime.utc(2026, 8, 10, 0, 0, 1),
+          reason: KaptanShutdownReason.safety,
+        ),
+      ),
+    );
+    await Future<void>.delayed(Duration.zero);
+
+    final state = container.read(observabilityControllerProvider);
+    expect(state.accessibilityAnnouncement, isNull);
+    expect(state.coalescedAlertCount, 1);
+  });
+
+  test(
+    'retains expected parser and semantic drops without ending observation',
+    () async {
+      final port = _ControlledDataPort();
+      final container = ProviderContainer(
+        overrides: [vehicleDataPortProvider.overrideWithValue(port)],
+      );
+      addTearDown(container.dispose);
+
+      container.read(observabilityControllerProvider);
+      await Future<void>.delayed(Duration.zero);
+
+      port.events.add(
+        const ObservationDropped(kind: ObservationDropKind.parser, count: 2),
+      );
+      port.events.add(
+        const ObservationDropped(kind: ObservationDropKind.semantic),
+      );
+      await Future<void>.delayed(Duration.zero);
+
+      final state = container.read(observabilityControllerProvider);
+      expect(state.status, ObservationStatus.receiving);
+      expect(state.parserDropCount, 2);
+      expect(state.semanticDropCount, 1);
+    },
+  );
+
+  test('treats a transport stream failure as a disconnected link', () async {
+    final port = _ControlledDataPort();
+    final container = ProviderContainer(
+      overrides: [vehicleDataPortProvider.overrideWithValue(port)],
+    );
+    addTearDown(container.dispose);
+
+    container.read(observabilityControllerProvider);
+    await Future<void>.delayed(Duration.zero);
+
+    port.events.addError(StateError('serial endpoint closed'));
+    await Future<void>.delayed(Duration.zero);
+
+    final state = container.read(observabilityControllerProvider);
+    expect(state.status, ObservationStatus.disconnected);
+    expect(state.parserDropCount, 0);
+    expect(state.semanticDropCount, 0);
+  });
+}
+
+class _ControlledDataPort implements VehicleDataPort {
+  final events = StreamController<VehicleDataUpdate>();
+
+  @override
+  bool get isReplay => false;
+
+  @override
+  String get label => 'Test transport';
+
+  @override
+  Future<void> close() => events.close();
+
+  @override
+  Stream<VehicleDataUpdate> observe() => events.stream;
+}