feat(wip): implement trip persistence through a local repository. Include loaded trips in the start page UI

frontend/test/current_trips_notifier_test.dart

@@ -0,0 +1,124 @@
+import 'package:anyway/domain/entities/landmark.dart';
+import 'package:anyway/domain/entities/landmark_type.dart';
+import 'package:anyway/domain/entities/preferences.dart';
+import 'package:anyway/domain/entities/trip.dart';
+import 'package:anyway/domain/repositories/trip_repository.dart';
+import 'package:anyway/presentation/providers/core_providers.dart';
+import 'package:anyway/presentation/providers/trip_provider.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+class _FakeTripRepository implements TripRepository {
+  _FakeTripRepository(this._trips);
+
+  final List<Trip> _trips;
+
+  @override
+  Future<void> deleteSavedTrip(String uuid) async {
+    _trips.removeWhere((trip) => trip.uuid == uuid);
+  }
+
+  @override
+  Future<Trip?> getSavedTrip(String uuid) async {
+    try {
+      return _trips.firstWhere((trip) => trip.uuid == uuid);
+    } on StateError {
+      return null;
+    }
+  }
+
+  @override
+  Future<List<Trip>> getSavedTrips() async {
+    return List.unmodifiable(_trips);
+  }
+
+  @override
+  Future<void> saveTrip(Trip trip) async {
+    _trips.removeWhere((t) => t.uuid == trip.uuid);
+    _trips.insert(0, trip);
+  }
+
+  // The following methods are not used in these tests.
+  @override
+  Future<Trip> getTrip({Preferences? preferences, String? tripUUID, List<Landmark>? landmarks}) {
+    throw UnimplementedError();
+  }
+
+  @override
+  Future<List<Landmark>> searchLandmarks(Preferences preferences) {
+    throw UnimplementedError();
+  }
+}
+
+Trip _buildTrip(String uuid) {
+  return Trip(
+    uuid: uuid,
+    totalTimeMinutes: 60,
+    landmarks: [
+      Landmark(
+        uuid: 'lm-$uuid',
+        name: 'Landmark $uuid',
+        location: const [0.0, 0.0],
+        type: const LandmarkType(type: LandmarkTypeEnum.sightseeing),
+      ),
+    ],
+  );
+}
+
+void main() {
+  test('currentTripsProvider loads saved trips on build', () async {
+    final repo = _FakeTripRepository([_buildTrip('trip-1')]);
+    final container = ProviderContainer(overrides: [
+      tripRepositoryProvider.overrideWithValue(repo),
+    ]);
+    addTearDown(container.dispose);
+
+    final trips = await container.read(currentTripsProvider.future);
+    expect(trips, hasLength(1));
+    expect(trips.first.uuid, 'trip-1');
+  });
+
+  test('saveTrip persists trips locally and updates provider state', () async {
+    final repo = _FakeTripRepository([_buildTrip('existing')]);
+    final container = ProviderContainer(overrides: [
+      tripRepositoryProvider.overrideWithValue(repo),
+    ]);
+    addTearDown(container.dispose);
+
+    await container.read(currentTripsProvider.future);
+    final notifier = container.read(currentTripsProvider.notifier);
+    await notifier.saveTrip(_buildTrip('fresh'));
+
+    final tripsState = container.read(currentTripsProvider);
+    expect(tripsState.value, isNotNull);
+    expect(tripsState.value!.first.uuid, 'fresh');
+
+    final repoTrips = await repo.getSavedTrips();
+    expect(repoTrips, hasLength(2));
+    expect(repoTrips.first.uuid, 'fresh');
+  });
+
+  test('deleteTrip removes trips from both provider state and repository', () async {
+    final repo = _FakeTripRepository([
+      _buildTrip('trip-1'),
+      _buildTrip('trip-2'),
+    ]);
+    final container = ProviderContainer(overrides: [
+      tripRepositoryProvider.overrideWithValue(repo),
+    ]);
+    addTearDown(container.dispose);
+
+    await container.read(currentTripsProvider.future);
+    final notifier = container.read(currentTripsProvider.notifier);
+    await notifier.deleteTrip('trip-1');
+
+    final tripsState = container.read(currentTripsProvider);
+    expect(tripsState.value, isNotNull);
+    expect(tripsState.value, hasLength(1));
+    expect(tripsState.value!.single.uuid, 'trip-2');
+
+    final repoTrips = await repo.getSavedTrips();
+    expect(repoTrips, hasLength(1));
+    expect(repoTrips.single.uuid, 'trip-2');
+  });
+}