ReelShort/test/engagement/engagement_repository_test.dart

import 'dart:convert';

import 'package:flutter_test/flutter_test.dart';
import 'package:fruitshorts/core/data/models/engagement_snapshot.dart';
import 'package:fruitshorts/core/data/repositories/engagement_repository.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:shared_preferences_platform_interface/in_memory_shared_preferences_async.dart';
import 'package:shared_preferences_platform_interface/shared_preferences_async_platform_interface.dart';

/// Mirrors the private key used by [SharedPreferencesEngagementRepository].
const _key = 'engagement.v1.demo-local-v1';

void main() {
  late SharedPreferencesAsync preferences;

  setUp(() {
    SharedPreferencesAsyncPlatform.instance =
        InMemorySharedPreferencesAsync.empty();
    preferences = SharedPreferencesAsync();
  });

  SharedPreferencesEngagementRepository repository() =>
      SharedPreferencesEngagementRepository(preferences: preferences);

  Future<EngagementSnapshot> loadRaw(String raw) async {
    await preferences.setString(_key, raw);
    return repository().load();
  }

  test('should_read_empty_snapshot_when_first_launch', () async {
    final snapshot = await repository().load();

    expect(snapshot.savedDramaIds, isEmpty);
    expect(snapshot.likedDramaIds, isEmpty);
    expect(snapshot.commentsByDrama, isEmpty);
  });

  test('should_survive_save_and_reload_round_trip_when_snapshot_is_stored', () async {
    await repository().save(
      const EngagementSnapshot(
        savedDramaIds: {'signal', 'city'},
        likedDramaIds: {'city'},
        commentsByDrama: {
          'signal': ['first note', 'second note'],
        },
      ),
    );

    final loaded = await repository().load();

    expect(loaded.savedDramaIds, {'signal', 'city'});
    expect(loaded.likedDramaIds, {'city'});
    expect(loaded.commentsByDrama, {
      'signal': ['first note', 'second note'],
    });
  });

  test('should_round_trip_as_empty_collections_when_snapshot_is_empty', () async {
    await repository().save(const EngagementSnapshot());

    final loaded = await repository().load();

    expect(loaded.savedDramaIds, isEmpty);
    expect(loaded.likedDramaIds, isEmpty);
    expect(loaded.commentsByDrama, isEmpty);
  });

  test('should_fall_back_to_empty_snapshot_when_payload_is_corrupt_or_not_an_object', () async {
    for (final raw in <String>[
      '',
      'not json at all',
      '[]',
      '"a bare string"',
      '42',
      'null',
    ]) {
      final snapshot = await loadRaw(raw);

      expect(snapshot.savedDramaIds, isEmpty, reason: raw);
      expect(snapshot.likedDramaIds, isEmpty, reason: raw);
      expect(snapshot.commentsByDrama, isEmpty, reason: raw);
    }
  });

  test('should_drop_mistyped_fields_when_payload_has_wrong_types', () async {
    final snapshot = await loadRaw(
      jsonEncode({
        'saved': 'signal',
        'liked': {'city': true},
        'comments': {
          'signal': 'a plain string',
          'city': ['kept', 7, null, true],
          'town': <Object>[],
        },
      }),
    );

    expect(snapshot.savedDramaIds, isEmpty);
    expect(snapshot.likedDramaIds, isEmpty);
    expect(snapshot.commentsByDrama, {
      'city': ['kept'],
      'town': <String>[],
    });
  });

  test('should_fall_back_per_field_when_payload_keys_are_missing', () async {
    final snapshot = await loadRaw(jsonEncode({'saved': ['signal']}));

    expect(snapshot.savedDramaIds, {'signal'});
    expect(snapshot.likedDramaIds, isEmpty);
    expect(snapshot.commentsByDrama, isEmpty);
  });

  test('should_write_only_json_primitives_when_saving', () async {
    await repository().save(
      const EngagementSnapshot(
        savedDramaIds: {'signal'},
        likedDramaIds: {'city'},
        commentsByDrama: {
          'signal': ['note'],
        },
      ),
    );

    final raw = await preferences.getString(_key);
    expect(raw, isNotNull);

    final decoded = jsonDecode(raw!) as Map<String, dynamic>;
    expect(decoded['saved'], ['signal']);
    expect(decoded['liked'], ['city']);
    expect(decoded['comments'], {
      'signal': ['note'],
    });
  });
}