Refactored method, added tests for DTS

lib/data/models/match.dart

@@ -68,7 +68,10 @@ class Match {
     'gameId': game.id,
     'groupId': group?.id,
     'playerIds': players.map((player) => player.id).toList(),
-    'scores': scores,
+    'scores': scores.map(
+      (playerId, scoreList) =>
+          MapEntry(playerId, scoreList.map((score) => score.toJson()).toList()),
+    ),
     'notes': notes,
   };
 }

lib/services/data_transfer_service.dart

@@ -70,6 +70,20 @@ class DataTransferService {
               'gameId': m.game.id,
               'groupId': m.group?.id,
               'playerIds': m.players.map((p) => p.id).toList(),
+              'scores': m.scores.map(
+                (playerId, scores) => MapEntry(
+                  playerId,
+                  scores
+                      .map(
+                        (s) => {
+                          'roundNumber': s.roundNumber,
+                          'score': s.score,
+                          'change': s.change,
+                        },
+                      )
+                      .toList(),
+                ),
+              ),
               'notes': m.notes,
             },
           )
@@ -127,40 +141,81 @@ class DataTransferService {
       final isValid = await _validateJsonSchema(jsonString);
       if (!isValid) return ImportResult.invalidSchema;
 
-      final Map<String, dynamic> decoded =
+      final decoded = json.decode(jsonString) as Map<String, dynamic>;
-          json.decode(jsonString) as Map<String, dynamic>;
 
-      final List<dynamic> playersJson =
+      await importDataToDatabase(db, decoded);
-          (decoded['players'] as List<dynamic>?) ?? [];
-      final List<dynamic> gamesJson =
-          (decoded['games'] as List<dynamic>?) ?? [];
-      final List<dynamic> groupsJson =
-          (decoded['groups'] as List<dynamic>?) ?? [];
-      final List<dynamic> teamsJson =
-          (decoded['teams'] as List<dynamic>?) ?? [];
-      final List<dynamic> matchesJson =
-          (decoded['matches'] as List<dynamic>?) ?? [];
 
-      // Import Players
+      return ImportResult.success;
-      final List<Player> importedPlayers = playersJson
+    } on FormatException catch (e, stack) {
+      print('[importData] FormatException');
+      print('[importData] $e');
+      print(stack);
+      return ImportResult.formatException;
+    } on Exception catch (e, stack) {
+      print('[importData] Exception');
+      print('[importData] $e');
+      print(stack);
+      return ImportResult.unknownException;
+    }
+  }
+
+  /// Imports parsed JSON data into the database.
+  @visibleForTesting
+  static Future<void> importDataToDatabase(
+    AppDatabase db,
+    Map<String, dynamic> decoded,
+  ) async {
+    final importedPlayers = parsePlayersFromJson(decoded);
+    final playerById = {for (final p in importedPlayers) p.id: p};
+
+    final importedGames = parseGamesFromJson(decoded);
+    final gameById = {for (final g in importedGames) g.id: g};
+
+    final importedGroups = parseGroupsFromJson(decoded, playerById);
+    final groupById = {for (final g in importedGroups) g.id: g};
+
+    final importedTeams = parseTeamsFromJson(decoded, playerById);
+
+    final importedMatches = parseMatchesFromJson(
+      decoded,
+      gameById,
+      groupById,
+      playerById,
+    );
+
+    await db.playerDao.addPlayersAsList(players: importedPlayers);
+    await db.gameDao.addGamesAsList(games: importedGames);
+    await db.groupDao.addGroupsAsList(groups: importedGroups);
+    await db.teamDao.addTeamsAsList(teams: importedTeams);
+    await db.matchDao.addMatchAsList(matches: importedMatches);
+  }
+
+  /// Parses players from JSON data.
+  @visibleForTesting
+  static List<Player> parsePlayersFromJson(Map<String, dynamic> decoded) {
+    final playersJson = (decoded['players'] as List<dynamic>?) ?? [];
+    return playersJson
         .map((p) => Player.fromJson(p as Map<String, dynamic>))
         .toList();
+  }
 
-      final Map<String, Player> playerById = {
+  /// Parses games from JSON data.
-        for (final p in importedPlayers) p.id: p,
+  @visibleForTesting
-      };
+  static List<Game> parseGamesFromJson(Map<String, dynamic> decoded) {
-
+    final gamesJson = (decoded['games'] as List<dynamic>?) ?? [];
-      // Import Games
+    return gamesJson
-      final List<Game> importedGames = gamesJson
         .map((g) => Game.fromJson(g as Map<String, dynamic>))
         .toList();
+  }
 
-      final Map<String, Game> gameById = {
+  /// Parses groups from JSON data.
-        for (final g in importedGames) g.id: g,
+  @visibleForTesting
-      };
+  static List<Group> parseGroupsFromJson(
-
+    Map<String, dynamic> decoded,
-      // Import Groups
+    Map<String, Player> playerById,
-      final List<Group> importedGroups = groupsJson.map((g) {
+  ) {
+    final groupsJson = (decoded['groups'] as List<dynamic>?) ?? [];
+    return groupsJson.map((g) {
       final map = g as Map<String, dynamic>;
       final memberIds = (map['memberIds'] as List<dynamic>? ?? [])
           .cast<String>();
@@ -178,13 +233,16 @@ class DataTransferService {
         createdAt: DateTime.parse(map['createdAt'] as String),
       );
     }).toList();
+  }
 
-      final Map<String, Group> groupById = {
+  /// Parses teams from JSON data.
-        for (final g in importedGroups) g.id: g,
+  @visibleForTesting
-      };
+  static List<Team> parseTeamsFromJson(
-
+    Map<String, dynamic> decoded,
-      // Import Teams
+    Map<String, Player> playerById,
-      final List<Team> importedTeams = teamsJson.map((t) {
+  ) {
+    final teamsJson = (decoded['teams'] as List<dynamic>?) ?? [];
+    return teamsJson.map((t) {
       final map = t as Map<String, dynamic>;
       final memberIds = (map['memberIds'] as List<dynamic>? ?? [])
           .cast<String>();
@@ -201,21 +259,30 @@ class DataTransferService {
         createdAt: DateTime.parse(map['createdAt'] as String),
       );
     }).toList();
+  }
 
-      // Import Matches
+  /// Parses matches from JSON data.
-      final List<Match> importedMatches = matchesJson.map((m) {
+  @visibleForTesting
+  static List<Match> parseMatchesFromJson(
+    Map<String, dynamic> decoded,
+    Map<String, Game> gameById,
+    Map<String, Group> groupById,
+    Map<String, Player> playerById,
+  ) {
+    final matchesJson = (decoded['matches'] as List<dynamic>?) ?? [];
+    return matchesJson.map((m) {
       final map = m as Map<String, dynamic>;
 
-        final String gameId = map['gameId'] as String;
+      final gameId = map['gameId'] as String;
-        final String? groupId = map['groupId'] as String?;
+      final groupId = map['groupId'] as String?;
-        final List<String> playerIds =
+      final playerIds = (map['playerIds'] as List<dynamic>? ?? [])
-            (map['playerIds'] as List<dynamic>? ?? []).cast<String>();
+          .cast<String>();
-        final DateTime? endedAt = map['endedAt'] != null
+      final endedAt = map['endedAt'] != null
           ? DateTime.parse(map['endedAt'] as String)
           : null;
 
-        final game = gameById[gameId];
+      final game = gameById[gameId] ?? createUnknownGame();
-        final group = (groupId == null) ? null : groupById[groupId];
+      final group = groupId != null ? groupById[groupId] : null;
       final players = playerIds
           .map((id) => playerById[id])
           .whereType<Player>()
@@ -224,15 +291,7 @@ class DataTransferService {
       return Match(
         id: map['id'] as String,
         name: map['name'] as String,
-          game:
+        game: game,
-              game ??
-              Game(
-                name: 'Unknown',
-                ruleset: Ruleset.singleWinner,
-                description: '',
-                color: GameColor.blue,
-                icon: '',
-              ),
         group: group,
         players: players,
         createdAt: DateTime.parse(map['createdAt'] as String),
@@ -240,26 +299,18 @@ class DataTransferService {
         notes: map['notes'] as String? ?? '',
       );
     }).toList();
-
-      // Import all data into the database
-      await db.playerDao.addPlayersAsList(players: importedPlayers);
-      await db.gameDao.addGamesAsList(games: importedGames);
-      await db.groupDao.addGroupsAsList(groups: importedGroups);
-      await db.teamDao.addTeamsAsList(teams: importedTeams);
-      await db.matchDao.addMatchAsList(matches: importedMatches);
-
-      return ImportResult.success;
-    } on FormatException catch (e, stack) {
-      print('[importData] FormatException');
-      print('[importData] $e');
-      print(stack);
-      return ImportResult.formatException;
-    } on Exception catch (e, stack) {
-      print('[importData] Exception');
-      print('[importData] $e');
-      print(stack);
-      return ImportResult.unknownException;
   }
+
+  /// Creates a fallback game when the referenced game is not found.
+  @visibleForTesting
+  static Game createUnknownGame() {
+    return Game(
+      name: 'Unknown',
+      ruleset: Ruleset.singleWinner,
+      description: '',
+      color: GameColor.blue,
+      icon: '',
+    );
   }
 
   /// Helper method to read file content from either bytes or path

test/services/data_transfer_service_test.dart

@@ -0,0 +1,802 @@
+import 'dart:convert';
+
+import 'package:clock/clock.dart';
+import 'package:drift/drift.dart' hide isNull, isNotNull;
+import 'package:drift/native.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:provider/provider.dart';
+import 'package:tallee/core/enums.dart';
+import 'package:tallee/data/db/database.dart';
+import 'package:tallee/data/models/game.dart';
+import 'package:tallee/data/models/group.dart';
+import 'package:tallee/data/models/match.dart';
+import 'package:tallee/data/models/player.dart';
+import 'package:tallee/data/models/score.dart';
+import 'package:tallee/data/models/team.dart';
+import 'package:tallee/services/data_transfer_service.dart';
+
+void main() {
+  late AppDatabase database;
+  late Player testPlayer1;
+  late Player testPlayer2;
+  late Player testPlayer3;
+  late Game testGame;
+  late Group testGroup;
+  late Team testTeam;
+  late Match testMatch;
+  final fixedDate = DateTime(2025, 11, 19, 0, 11, 23);
+  final fakeClock = Clock(() => fixedDate);
+
+  setUp(() {
+    database = AppDatabase(
+      DatabaseConnection(
+        NativeDatabase.memory(),
+        closeStreamsSynchronously: true,
+      ),
+    );
+
+    withClock(fakeClock, () {
+      testPlayer1 = Player(name: 'Alice', description: 'First test player');
+      testPlayer2 = Player(name: 'Bob', description: 'Second test player');
+      testPlayer3 = Player(name: 'Charlie', description: 'Third player');
+
+      testGame = Game(
+        name: 'Chess',
+        ruleset: Ruleset.singleWinner,
+        description: 'Strategic board game',
+        color: GameColor.blue,
+        icon: 'chess_icon',
+      );
+
+      testGroup = Group(
+        name: 'Test Group',
+        description: 'Group for testing',
+        members: [testPlayer1, testPlayer2],
+      );
+
+      testTeam = Team(name: 'Test Team', members: [testPlayer1, testPlayer2]);
+
+      testMatch = Match(
+        name: 'Test Match',
+        game: testGame,
+        group: testGroup,
+        players: [testPlayer1, testPlayer2],
+        notes: 'Test notes',
+        scores: {
+          testPlayer1.id: [
+            Score(roundNumber: 1, score: 10, change: 10),
+            Score(roundNumber: 2, score: 20, change: 10),
+          ],
+          testPlayer2.id: [
+            Score(roundNumber: 1, score: 15, change: 15),
+            Score(roundNumber: 2, score: 25, change: 10),
+          ],
+        },
+      );
+    });
+  });
+
+  tearDown(() async {
+    await database.close();
+  });
+
+  // Helper for getting BuildContext
+  Future<BuildContext> getContext(WidgetTester tester) async {
+    // Minimal widget with Provider
+    await tester.pumpWidget(
+      Provider<AppDatabase>.value(
+        value: database,
+        child: MaterialApp(
+          home: Builder(
+            builder: (context) {
+              return Container();
+            },
+          ),
+        ),
+      ),
+    );
+    final BuildContext context = tester.element(find.byType(Container));
+    return context;
+  }
+
+  group('DataTransferService Tests', () {
+    testWidgets('deleteAllData()', (tester) async {
+      await database.playerDao.addPlayer(player: testPlayer1);
+      await database.gameDao.addGame(game: testGame);
+      await database.groupDao.addGroup(group: testGroup);
+      await database.teamDao.addTeam(team: testTeam);
+      await database.matchDao.addMatch(match: testMatch);
+
+      var playerCount = await database.playerDao.getPlayerCount();
+      var gameCount = await database.gameDao.getGameCount();
+      var groupCount = await database.groupDao.getGroupCount();
+      var teamCount = await database.teamDao.getTeamCount();
+      var matchCount = await database.matchDao.getMatchCount();
+
+      expect(playerCount, greaterThan(0));
+      expect(gameCount, greaterThan(0));
+      expect(groupCount, greaterThan(0));
+      expect(teamCount, greaterThan(0));
+      expect(matchCount, greaterThan(0));
+
+      final ctx = await getContext(tester);
+      await DataTransferService.deleteAllData(ctx);
+
+      playerCount = await database.playerDao.getPlayerCount();
+      gameCount = await database.gameDao.getGameCount();
+      groupCount = await database.groupDao.getGroupCount();
+      teamCount = await database.teamDao.getTeamCount();
+      matchCount = await database.matchDao.getMatchCount();
+
+      expect(playerCount, 0);
+      expect(gameCount, 0);
+      expect(groupCount, 0);
+      expect(teamCount, 0);
+      expect(matchCount, 0);
+    });
+
+    group('getAppDataAsJson()', () {
+      group('Whole export', () {
+        testWidgets('Exporting app data works correctly', (tester) async {
+          await database.playerDao.addPlayer(player: testPlayer1);
+          await database.playerDao.addPlayer(player: testPlayer2);
+          await database.gameDao.addGame(game: testGame);
+          await database.groupDao.addGroup(group: testGroup);
+          await database.teamDao.addTeam(team: testTeam);
+          await database.matchDao.addMatch(match: testMatch);
+
+          final ctx = await getContext(tester);
+          final jsonString = await DataTransferService.getAppDataAsJson(ctx);
+
+          expect(jsonString, isNotEmpty);
+
+          final decoded = json.decode(jsonString) as Map<String, dynamic>;
+
+          expect(decoded.containsKey('players'), true);
+          expect(decoded.containsKey('games'), true);
+          expect(decoded.containsKey('groups'), true);
+          expect(decoded.containsKey('teams'), true);
+          expect(decoded.containsKey('matches'), true);
+
+          final players = decoded['players'] as List<dynamic>;
+          final games = decoded['games'] as List<dynamic>;
+          final groups = decoded['groups'] as List<dynamic>;
+          final teams = decoded['teams'] as List<dynamic>;
+          final matches = decoded['matches'] as List<dynamic>;
+
+          expect(players.length, 2);
+          expect(games.length, 1);
+          expect(groups.length, 1);
+          expect(teams.length, 1);
+          expect(matches.length, 1);
+        });
+
+        testWidgets('Exporting empty data works correctly', (tester) async {
+          final ctx = await getContext(tester);
+          final jsonString = await DataTransferService.getAppDataAsJson(ctx);
+
+          final decoded = json.decode(jsonString) as Map<String, dynamic>;
+
+          final players = decoded['players'] as List<dynamic>;
+          final games = decoded['games'] as List<dynamic>;
+          final groups = decoded['groups'] as List<dynamic>;
+          final teams = decoded['teams'] as List<dynamic>;
+          final matches = decoded['matches'] as List<dynamic>;
+
+          expect(players, isEmpty);
+          expect(games, isEmpty);
+          expect(groups, isEmpty);
+          expect(teams, isEmpty);
+          expect(matches, isEmpty);
+        });
+      });
+
+      group('Specific data', () {
+        testWidgets('Player data is correct', (tester) async {
+          await database.playerDao.addPlayer(player: testPlayer1);
+
+          final ctx = await getContext(tester);
+          final jsonString = await DataTransferService.getAppDataAsJson(ctx);
+          final decoded = json.decode(jsonString) as Map<String, dynamic>;
+          final players = decoded['players'] as List<dynamic>;
+          final playerData = players[0] as Map<String, dynamic>;
+
+          expect(playerData['id'], testPlayer1.id);
+          expect(playerData['name'], testPlayer1.name);
+          expect(playerData['description'], testPlayer1.description);
+          expect(
+            playerData['createdAt'],
+            testPlayer1.createdAt.toIso8601String(),
+          );
+        });
+
+        testWidgets('Game data is correct', (tester) async {
+          await database.gameDao.addGame(game: testGame);
+
+          final ctx = await getContext(tester);
+          final jsonString = await DataTransferService.getAppDataAsJson(ctx);
+          final decoded = json.decode(jsonString) as Map<String, dynamic>;
+          final games = decoded['games'] as List<dynamic>;
+          final gameData = games[0] as Map<String, dynamic>;
+
+          expect(gameData['id'], testGame.id);
+          expect(gameData['name'], testGame.name);
+          expect(gameData['ruleset'], testGame.ruleset.name);
+          expect(gameData['description'], testGame.description);
+          expect(gameData['color'], testGame.color.name);
+          expect(gameData['icon'], testGame.icon);
+        });
+
+        testWidgets('Group data is correct', (tester) async {
+          await database.playerDao.addPlayer(player: testPlayer1);
+          await database.playerDao.addPlayer(player: testPlayer2);
+          await database.groupDao.addGroup(group: testGroup);
+
+          final ctx = await getContext(tester);
+          final jsonString = await DataTransferService.getAppDataAsJson(ctx);
+          final decoded = json.decode(jsonString) as Map<String, dynamic>;
+          final groups = decoded['groups'] as List<dynamic>;
+          final groupData = groups[0] as Map<String, dynamic>;
+
+          expect(groupData['id'], testGroup.id);
+          expect(groupData['name'], testGroup.name);
+          expect(groupData['description'], testGroup.description);
+          expect(groupData['memberIds'], isA<List>());
+
+          final memberIds = groupData['memberIds'] as List<dynamic>;
+          expect(memberIds.length, 2);
+          expect(memberIds, containsAll([testPlayer1.id, testPlayer2.id]));
+        });
+
+        testWidgets('Team data is correct', (tester) async {
+          await database.teamDao.addTeam(team: testTeam);
+
+          final ctx = await getContext(tester);
+          final jsonString = await DataTransferService.getAppDataAsJson(ctx);
+          final decoded = json.decode(jsonString) as Map<String, dynamic>;
+          final teams = decoded['teams'] as List<dynamic>;
+
+          expect(teams.length, 1);
+
+          final teamData = teams[0] as Map<String, dynamic>;
+
+          expect(teamData['id'], testTeam.id);
+          expect(teamData['name'], testTeam.name);
+          expect(teamData['memberIds'], isA<List>());
+
+          // Note: In this system, teams don't have independent members.
+          // Team members are only tracked through matches via PlayerMatchTable.
+          // Therefore, memberIds will be empty for standalone teams.
+          final memberIds = teamData['memberIds'] as List<dynamic>;
+          expect(memberIds, isEmpty);
+        });
+
+        testWidgets('Match data is correct', (tester) async {
+          await database.playerDao.addPlayersAsList(
+            players: [testPlayer1, testPlayer2],
+          );
+          await database.gameDao.addGame(game: testGame);
+          await database.groupDao.addGroup(group: testGroup);
+          await database.matchDao.addMatch(match: testMatch);
+
+          final ctx = await getContext(tester);
+          final jsonString = await DataTransferService.getAppDataAsJson(ctx);
+          final decoded = json.decode(jsonString) as Map<String, dynamic>;
+          final matches = decoded['matches'] as List<dynamic>;
+          final matchData = matches[0] as Map<String, dynamic>;
+
+          expect(matchData['id'], testMatch.id);
+          expect(matchData['name'], testMatch.name);
+          expect(matchData['gameId'], testGame.id);
+          expect(matchData['groupId'], testGroup.id);
+          expect(matchData['playerIds'], isA<List>());
+          expect(matchData['notes'], testMatch.notes);
+
+          // Check player ids
+          final playerIds = matchData['playerIds'] as List<String>;
+          expect(playerIds.length, 2);
+          expect(playerIds, containsAll([testPlayer1.id, testPlayer2.id]));
+
+          // Check scores structure
+          final scoresJson = matchData['scores'] as Map<String, dynamic>;
+          expect(scoresJson, isA<Map<String, dynamic>>());
+
+          final scores = scoresJson.map(
+            (playerId, scoreList) => MapEntry(
+              playerId,
+              (scoreList as List)
+                  .map((s) => Score.fromJson(s as Map<String, dynamic>))
+                  .toList(),
+            ),
+          );
+
+          expect(scores, isA<Map<String, List<Score>>>());
+
+          /* Player 1 scores */
+          // General structure
+          expect(scores[testPlayer1.id], isNotNull);
+          expect(scores[testPlayer1.id]!.length, 2);
+
+          // Round 1
+          expect(scores[testPlayer1.id]![0].roundNumber, 1);
+          expect(scores[testPlayer1.id]![0].score, 10);
+          expect(scores[testPlayer1.id]![0].change, 10);
+
+          // Round 2
+          expect(scores[testPlayer1.id]![1].roundNumber, 2);
+          expect(scores[testPlayer1.id]![1].score, 20);
+          expect(scores[testPlayer1.id]![1].change, 10);
+
+          /* Player 2 scores */
+          // General structure
+          expect(scores[testPlayer2.id], isNotNull);
+          expect(scores[testPlayer2.id]!.length, 2);
+
+          // Round 1
+          expect(scores[testPlayer2.id]![0].roundNumber, 1);
+          expect(scores[testPlayer2.id]![0].score, 15);
+          expect(scores[testPlayer2.id]![0].change, 15);
+
+          // Round 2
+          expect(scores[testPlayer2.id]![1].roundNumber, 2);
+          expect(scores[testPlayer2.id]![1].score, 25);
+          expect(scores[testPlayer2.id]![1].change, 10);
+        });
+
+        testWidgets('Match without group is handled correctly', (tester) async {
+          final matchWithoutGroup = Match(
+            name: 'No Group Match',
+            game: testGame,
+            group: null,
+            players: [testPlayer1],
+            notes: 'No group',
+          );
+
+          await database.playerDao.addPlayer(player: testPlayer1);
+          await database.gameDao.addGame(game: testGame);
+          await database.matchDao.addMatch(match: matchWithoutGroup);
+
+          final ctx = await getContext(tester);
+          final jsonString = await DataTransferService.getAppDataAsJson(ctx);
+          final decoded = json.decode(jsonString) as Map<String, dynamic>;
+          final matches = decoded['matches'] as List<dynamic>;
+          final matchData = matches[0] as Map<String, dynamic>;
+
+          expect(matchData['groupId'], isNull);
+        });
+
+        testWidgets('Match with endedAt is handled correctly', (tester) async {
+          final endedDate = DateTime(2025, 12, 1, 10, 0, 0);
+          final endedMatch = Match(
+            name: 'Ended Match',
+            game: testGame,
+            players: [testPlayer1],
+            endedAt: endedDate,
+            notes: 'Finished',
+          );
+
+          await database.playerDao.addPlayer(player: testPlayer1);
+          await database.gameDao.addGame(game: testGame);
+          await database.matchDao.addMatch(match: endedMatch);
+
+          final ctx = await getContext(tester);
+          final jsonString = await DataTransferService.getAppDataAsJson(ctx);
+          final decoded = json.decode(jsonString) as Map<String, dynamic>;
+          final matches = decoded['matches'] as List<dynamic>;
+          final matchData = matches[0] as Map<String, dynamic>;
+
+          expect(matchData['endedAt'], endedDate.toIso8601String());
+        });
+
+        testWidgets('Structure is consistent', (tester) async {
+          await database.playerDao.addPlayer(player: testPlayer1);
+          await database.gameDao.addGame(game: testGame);
+
+          final ctx = await getContext(tester);
+          final jsonString1 = await DataTransferService.getAppDataAsJson(ctx);
+          final jsonString2 = await DataTransferService.getAppDataAsJson(ctx);
+
+          expect(jsonString1, equals(jsonString2));
+        });
+
+        testWidgets('Empty match notes is handled correctly', (tester) async {
+          final matchWithEmptyNotes = Match(
+            name: 'Empty Notes Match',
+            game: testGame,
+            players: [testPlayer1],
+            notes: '',
+          );
+
+          await database.playerDao.addPlayer(player: testPlayer1);
+          await database.gameDao.addGame(game: testGame);
+          await database.matchDao.addMatch(match: matchWithEmptyNotes);
+
+          final ctx = await getContext(tester);
+          final jsonString = await DataTransferService.getAppDataAsJson(ctx);
+          final decoded = json.decode(jsonString) as Map<String, dynamic>;
+          final matches = decoded['matches'] as List<dynamic>;
+          final matchData = matches[0] as Map<String, dynamic>;
+
+          expect(matchData['notes'], '');
+        });
+
+        testWidgets('Multiple players in match is handled correctly', (
+          tester,
+        ) async {
+          final multiPlayerMatch = Match(
+            name: 'Multi Player Match',
+            game: testGame,
+            players: [testPlayer1, testPlayer2, testPlayer3],
+            notes: 'Three players',
+          );
+
+          await database.playerDao.addPlayersAsList(
+            players: [testPlayer1, testPlayer2, testPlayer3],
+          );
+          await database.gameDao.addGame(game: testGame);
+          await database.matchDao.addMatch(match: multiPlayerMatch);
+
+          final ctx = await getContext(tester);
+          final jsonString = await DataTransferService.getAppDataAsJson(ctx);
+          final decoded = json.decode(jsonString) as Map<String, dynamic>;
+          final matches = decoded['matches'] as List<dynamic>;
+          final matchData = matches[0] as Map<String, dynamic>;
+
+          final playerIds = matchData['playerIds'] as List<dynamic>;
+          expect(playerIds.length, 3);
+          expect(
+            playerIds,
+            containsAll([testPlayer1.id, testPlayer2.id, testPlayer3.id]),
+          );
+        });
+
+        testWidgets('All game colors are handled correctly', (tester) async {
+          final games = [
+            Game(
+              name: 'Red Game',
+              ruleset: Ruleset.singleWinner,
+              color: GameColor.red,
+              icon: 'icon',
+            ),
+            Game(
+              name: 'Blue Game',
+              ruleset: Ruleset.singleWinner,
+              color: GameColor.blue,
+              icon: 'icon',
+            ),
+            Game(
+              name: 'Green Game',
+              ruleset: Ruleset.singleWinner,
+              color: GameColor.green,
+              icon: 'icon',
+            ),
+          ];
+
+          await database.gameDao.addGamesAsList(games: games);
+
+          final ctx = await getContext(tester);
+          final jsonString = await DataTransferService.getAppDataAsJson(ctx);
+          final decoded = json.decode(jsonString) as Map<String, dynamic>;
+          final gamesJson = decoded['games'] as List<dynamic>;
+
+          expect(gamesJson.length, 3);
+          expect(
+            gamesJson.map((g) => g['color']),
+            containsAll(['red', 'blue', 'green']),
+          );
+        });
+
+        testWidgets('All rulesets are handled correctly', (tester) async {
+          final games = [
+            Game(
+              name: 'Highest Score Game',
+              ruleset: Ruleset.highestScore,
+              color: GameColor.blue,
+              icon: 'icon',
+            ),
+            Game(
+              name: 'Lowest Score Game',
+              ruleset: Ruleset.lowestScore,
+              color: GameColor.blue,
+              icon: 'icon',
+            ),
+            Game(
+              name: 'Single Winner',
+              ruleset: Ruleset.singleWinner,
+              color: GameColor.blue,
+              icon: 'icon',
+            ),
+          ];
+
+          await database.gameDao.addGamesAsList(games: games);
+
+          final ctx = await getContext(tester);
+          final jsonString = await DataTransferService.getAppDataAsJson(ctx);
+          final decoded = json.decode(jsonString) as Map<String, dynamic>;
+          final gamesJson = decoded['games'] as List<dynamic>;
+
+          expect(gamesJson.length, 3);
+          expect(
+            gamesJson.map((g) => g['ruleset']),
+            containsAll(['highestScore', 'lowestScore', 'singleWinner']),
+          );
+        });
+      });
+    });
+
+    group('Parse Methods', () {
+      test('parsePlayersFromJson()', () {
+        final jsonMap = {
+          'players': [
+            {
+              'id': testPlayer1.id,
+              'name': testPlayer1.name,
+              'description': testPlayer1.description,
+              'createdAt': testPlayer1.createdAt.toIso8601String(),
+            },
+            {
+              'id': testPlayer2.id,
+              'name': testPlayer2.name,
+              'description': testPlayer2.description,
+              'createdAt': testPlayer2.createdAt.toIso8601String(),
+            },
+          ],
+        };
+
+        final players = DataTransferService.parsePlayersFromJson(jsonMap);
+
+        expect(players.length, 2);
+        expect(players[0].id, testPlayer1.id);
+        expect(players[0].name, testPlayer1.name);
+        expect(players[1].id, testPlayer2.id);
+        expect(players[1].name, testPlayer2.name);
+      });
+
+      test('parsePlayersFromJson() empty list', () {
+        final jsonMap = {'players': []};
+        final players = DataTransferService.parsePlayersFromJson(jsonMap);
+        expect(players, isEmpty);
+      });
+
+      test('parsePlayersFromJson() missing key', () {
+        final jsonMap = <String, dynamic>{};
+        final players = DataTransferService.parsePlayersFromJson(jsonMap);
+        expect(players, isEmpty);
+      });
+
+      test('parseGamesFromJson()', () {
+        final jsonMap = {
+          'games': [
+            {
+              'id': testGame.id,
+              'name': testGame.name,
+              'ruleset': testGame.ruleset.name,
+              'description': testGame.description,
+              'color': testGame.color.name,
+              'icon': testGame.icon,
+              'createdAt': testGame.createdAt.toIso8601String(),
+            },
+          ],
+        };
+
+        final games = DataTransferService.parseGamesFromJson(jsonMap);
+
+        expect(games.length, 1);
+        expect(games[0].id, testGame.id);
+        expect(games[0].name, testGame.name);
+        expect(games[0].ruleset, testGame.ruleset);
+      });
+
+      test('parseGroupsFromJson()', () {
+        final playerById = {
+          testPlayer1.id: testPlayer1,
+          testPlayer2.id: testPlayer2,
+        };
+
+        final jsonMap = {
+          'groups': [
+            {
+              'id': testGroup.id,
+              'name': testGroup.name,
+              'description': testGroup.description,
+              'memberIds': [testPlayer1.id, testPlayer2.id],
+              'createdAt': testGroup.createdAt.toIso8601String(),
+            },
+          ],
+        };
+
+        final groups = DataTransferService.parseGroupsFromJson(
+          jsonMap,
+          playerById,
+        );
+
+        expect(groups.length, 1);
+        expect(groups[0].id, testGroup.id);
+        expect(groups[0].name, testGroup.name);
+        expect(groups[0].members.length, 2);
+        expect(groups[0].members[0].id, testPlayer1.id);
+        expect(groups[0].members[1].id, testPlayer2.id);
+      });
+
+      test('parseGroupsFromJson() ignores invalid player ids', () {
+        final playerById = {testPlayer1.id: testPlayer1};
+
+        final jsonMap = {
+          'groups': [
+            {
+              'id': testGroup.id,
+              'name': testGroup.name,
+              'description': testGroup.description,
+              'memberIds': [testPlayer1.id, 'invalid-id'],
+              'createdAt': testGroup.createdAt.toIso8601String(),
+            },
+          ],
+        };
+
+        final groups = DataTransferService.parseGroupsFromJson(
+          jsonMap,
+          playerById,
+        );
+
+        expect(groups.length, 1);
+        expect(groups[0].members.length, 1);
+        expect(groups[0].members[0].id, testPlayer1.id);
+      });
+
+      test('parseTeamsFromJson()', () {
+        final playerById = {testPlayer1.id: testPlayer1};
+
+        final jsonMap = {
+          'teams': [
+            {
+              'id': testTeam.id,
+              'name': testTeam.name,
+              'memberIds': [testPlayer1.id],
+              'createdAt': testTeam.createdAt.toIso8601String(),
+            },
+          ],
+        };
+
+        final teams = DataTransferService.parseTeamsFromJson(
+          jsonMap,
+          playerById,
+        );
+
+        expect(teams.length, 1);
+        expect(teams[0].id, testTeam.id);
+        expect(teams[0].name, testTeam.name);
+        expect(teams[0].members.length, 1);
+        expect(teams[0].members[0].id, testPlayer1.id);
+      });
+
+      test('parseMatchesFromJson()', () {
+        final playerById = {
+          testPlayer1.id: testPlayer1,
+          testPlayer2.id: testPlayer2,
+        };
+        final gameById = {testGame.id: testGame};
+        final groupById = {testGroup.id: testGroup};
+
+        final jsonMap = {
+          'matches': [
+            {
+              'id': testMatch.id,
+              'name': testMatch.name,
+              'gameId': testGame.id,
+              'groupId': testGroup.id,
+              'playerIds': [testPlayer1.id, testPlayer2.id],
+              'notes': testMatch.notes,
+              'createdAt': testMatch.createdAt.toIso8601String(),
+            },
+          ],
+        };
+
+        final matches = DataTransferService.parseMatchesFromJson(
+          jsonMap,
+          gameById,
+          groupById,
+          playerById,
+        );
+
+        expect(matches.length, 1);
+        expect(matches[0].id, testMatch.id);
+        expect(matches[0].name, testMatch.name);
+        expect(matches[0].game.id, testGame.id);
+        expect(matches[0].group?.id, testGroup.id);
+        expect(matches[0].players.length, 2);
+      });
+
+      test('parseMatchesFromJson() creates unknown game for missing game', () {
+        final playerById = {testPlayer1.id: testPlayer1};
+        final gameById = <String, Game>{};
+        final groupById = <String, Group>{};
+
+        final jsonMap = {
+          'matches': [
+            {
+              'id': testMatch.id,
+              'name': testMatch.name,
+              'gameId': 'non-existent-game-id',
+              'playerIds': [testPlayer1.id],
+              'notes': '',
+              'createdAt': testMatch.createdAt.toIso8601String(),
+            },
+          ],
+        };
+
+        final matches = DataTransferService.parseMatchesFromJson(
+          jsonMap,
+          gameById,
+          groupById,
+          playerById,
+        );
+
+        expect(matches.length, 1);
+        expect(matches[0].game.name, 'Unknown');
+        expect(matches[0].game.ruleset, Ruleset.singleWinner);
+      });
+
+      test('parseMatchesFromJson() handles null group', () {
+        final playerById = {testPlayer1.id: testPlayer1};
+        final gameById = {testGame.id: testGame};
+        final groupById = <String, Group>{};
+
+        final jsonMap = {
+          'matches': [
+            {
+              'id': testMatch.id,
+              'name': testMatch.name,
+              'gameId': testGame.id,
+              'groupId': null,
+              'playerIds': [testPlayer1.id],
+              'notes': '',
+              'createdAt': testMatch.createdAt.toIso8601String(),
+            },
+          ],
+        };
+
+        final matches = DataTransferService.parseMatchesFromJson(
+          jsonMap,
+          gameById,
+          groupById,
+          playerById,
+        );
+
+        expect(matches.length, 1);
+        expect(matches[0].group, isNull);
+      });
+
+      test('parseMatchesFromJson() handles endedAt', () {
+        final playerById = {testPlayer1.id: testPlayer1};
+        final gameById = {testGame.id: testGame};
+        final groupById = <String, Group>{};
+        final endedDate = DateTime(2025, 12, 1, 10, 0, 0);
+
+        final jsonMap = {
+          'matches': [
+            {
+              'id': testMatch.id,
+              'name': testMatch.name,
+              'gameId': testGame.id,
+              'playerIds': [testPlayer1.id],
+              'notes': '',
+              'createdAt': testMatch.createdAt.toIso8601String(),
+              'endedAt': endedDate.toIso8601String(),
+            },
+          ],
+        };
+
+        final matches = DataTransferService.parseMatchesFromJson(
+          jsonMap,
+          gameById,
+          groupById,
+          playerById,
+        );
+
+        expect(matches.length, 1);
+        expect(matches[0].endedAt, endedDate);
+      });
+    });
+  });
+}