feat(01-01): add core infrastructure, localization, and Wave 0 tests

- AppDatabase with schemaVersion 1, in-memory executor for testing
- Database provider with @Riverpod(keepAlive: true)
- AppTheme with sage green seed ColorScheme and warm surface overrides
- ThemeNotifier with SharedPreferences persistence, defaults to system
- Full German ARB localization (15 keys) with proper umlauts
- Minimal main.dart with ProviderScope placeholder
- Drift schema v1 captured via make-migrations
- All .g.dart files generated via build_runner
- Wave 0 tests: database (3), color scheme (6), theme (3), localization (2) -- 14 total, all passing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

drift_schemas/household_keeper/drift_schema_v1.json

@@ -0,0 +1,10 @@
+{
+  "_meta": {
+    "description": "This file contains a serialized version of schema entities for drift.",
+    "version": "1.3.0"
+  },
+  "options": {
+    "store_date_time_values_as_text": false
+  },
+  "entities": []
+}

lib/core/database/database.dart

@@ -0,0 +1,22 @@
+import 'package:drift/drift.dart';
+import 'package:drift_flutter/drift_flutter.dart';
+import 'package:path_provider/path_provider.dart';
+
+part 'database.g.dart';
+
+@DriftDatabase(tables: [])
+class AppDatabase extends _$AppDatabase {
+  AppDatabase([QueryExecutor? executor]) : super(executor ?? _openConnection());
+
+  @override
+  int get schemaVersion => 1;
+
+  static QueryExecutor _openConnection() {
+    return driftDatabase(
+      name: 'household_keeper',
+      native: const DriftNativeOptions(
+        databaseDirectory: getApplicationSupportDirectory,
+      ),
+    );
+  }
+}

lib/core/database/database.g.dart

@@ -0,0 +1,19 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'database.dart';
+
+// ignore_for_file: type=lint
+abstract class _$AppDatabase extends GeneratedDatabase {
+  _$AppDatabase(QueryExecutor e) : super(e);
+  $AppDatabaseManager get managers => $AppDatabaseManager(this);
+  @override
+  Iterable<TableInfo<Table, Object?>> get allTables =>
+      allSchemaEntities.whereType<TableInfo<Table, Object?>>();
+  @override
+  List<DatabaseSchemaEntity> get allSchemaEntities => [];
+}
+
+class $AppDatabaseManager {
+  final _$AppDatabase _db;
+  $AppDatabaseManager(this._db);
+}

lib/core/providers/database_provider.dart

@@ -0,0 +1,11 @@
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+import 'package:household_keeper/core/database/database.dart';
+
+part 'database_provider.g.dart';
+
+@Riverpod(keepAlive: true)
+AppDatabase appDatabase(Ref ref) {
+  final db = AppDatabase();
+  ref.onDispose(db.close);
+  return db;
+}

lib/core/providers/database_provider.g.dart

@@ -0,0 +1,51 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'database_provider.dart';
+
+// **************************************************************************
+// RiverpodGenerator
+// **************************************************************************
+
+// GENERATED CODE - DO NOT MODIFY BY HAND
+// ignore_for_file: type=lint, type=warning
+
+@ProviderFor(appDatabase)
+final appDatabaseProvider = AppDatabaseProvider._();
+
+final class AppDatabaseProvider
+    extends $FunctionalProvider<AppDatabase, AppDatabase, AppDatabase>
+    with $Provider<AppDatabase> {
+  AppDatabaseProvider._()
+    : super(
+        from: null,
+        argument: null,
+        retry: null,
+        name: r'appDatabaseProvider',
+        isAutoDispose: false,
+        dependencies: null,
+        $allTransitiveDependencies: null,
+      );
+
+  @override
+  String debugGetCreateSourceHash() => _$appDatabaseHash();
+
+  @$internal
+  @override
+  $ProviderElement<AppDatabase> $createElement($ProviderPointer pointer) =>
+      $ProviderElement(pointer);
+
+  @override
+  AppDatabase create(Ref ref) {
+    return appDatabase(ref);
+  }
+
+  /// {@macro riverpod.override_with_value}
+  Override overrideWithValue(AppDatabase value) {
+    return $ProviderOverride(
+      origin: this,
+      providerOverride: $SyncValueProvider<AppDatabase>(value),
+    );
+  }
+}
+
+String _$appDatabaseHash() => r'59cce38d45eeaba199eddd097d8e149d66f9f3e1';

lib/core/theme/app_theme.dart

@@ -0,0 +1,45 @@
+import 'package:flutter/material.dart';
+
+class AppTheme {
+  AppTheme._();
+
+  static ThemeData lightTheme() {
+    final colorScheme = ColorScheme.fromSeed(
+      seedColor: const Color(0xFF7A9A6D),
+      brightness: Brightness.light,
+      dynamicSchemeVariant: DynamicSchemeVariant.tonalSpot,
+    ).copyWith(
+      surface: const Color(0xFFF5F0E8),
+      surfaceContainerLowest: const Color(0xFFFAF7F2),
+      surfaceContainerLow: const Color(0xFFF2EDE4),
+      surfaceContainer: const Color(0xFFEDE7DC),
+      surfaceContainerHigh: const Color(0xFFE7E0D5),
+      surfaceContainerHighest: const Color(0xFFE0D9CE),
+    );
+
+    return ThemeData(
+      useMaterial3: true,
+      colorScheme: colorScheme,
+    );
+  }
+
+  static ThemeData darkTheme() {
+    final colorScheme = ColorScheme.fromSeed(
+      seedColor: const Color(0xFF7A9A6D),
+      brightness: Brightness.dark,
+      dynamicSchemeVariant: DynamicSchemeVariant.tonalSpot,
+    ).copyWith(
+      surface: const Color(0xFF2A2520),
+      surfaceContainerLowest: const Color(0xFF1E1A16),
+      surfaceContainerLow: const Color(0xFF322D27),
+      surfaceContainer: const Color(0xFF3A342E),
+      surfaceContainerHigh: const Color(0xFF433D36),
+      surfaceContainerHighest: const Color(0xFF4D463F),
+    );
+
+    return ThemeData(
+      useMaterial3: true,
+      colorScheme: colorScheme,
+    );
+  }
+}

lib/core/theme/theme_provider.dart

@@ -0,0 +1,53 @@
+import 'package:flutter/material.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+part 'theme_provider.g.dart';
+
+const _themeModeKey = 'theme_mode';
+
+@riverpod
+class ThemeNotifier extends _$ThemeNotifier {
+  @override
+  ThemeMode build() {
+    _loadPersistedThemeMode();
+    return ThemeMode.system;
+  }
+
+  Future<void> _loadPersistedThemeMode() async {
+    final prefs = await SharedPreferences.getInstance();
+    final persisted = prefs.getString(_themeModeKey);
+    if (persisted != null) {
+      state = _themeModeFromString(persisted);
+    }
+  }
+
+  Future<void> setThemeMode(ThemeMode mode) async {
+    state = mode;
+    final prefs = await SharedPreferences.getInstance();
+    await prefs.setString(_themeModeKey, _themeModeToString(mode));
+  }
+
+  static ThemeMode _themeModeFromString(String? value) {
+    switch (value) {
+      case 'light':
+        return ThemeMode.light;
+      case 'dark':
+        return ThemeMode.dark;
+      case 'system':
+      default:
+        return ThemeMode.system;
+    }
+  }
+
+  static String _themeModeToString(ThemeMode mode) {
+    switch (mode) {
+      case ThemeMode.light:
+        return 'light';
+      case ThemeMode.dark:
+        return 'dark';
+      case ThemeMode.system:
+        return 'system';
+    }
+  }
+}

lib/core/theme/theme_provider.g.dart

@@ -0,0 +1,62 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'theme_provider.dart';
+
+// **************************************************************************
+// RiverpodGenerator
+// **************************************************************************
+
+// GENERATED CODE - DO NOT MODIFY BY HAND
+// ignore_for_file: type=lint, type=warning
+
+@ProviderFor(ThemeNotifier)
+final themeProvider = ThemeNotifierProvider._();
+
+final class ThemeNotifierProvider
+    extends $NotifierProvider<ThemeNotifier, ThemeMode> {
+  ThemeNotifierProvider._()
+    : super(
+        from: null,
+        argument: null,
+        retry: null,
+        name: r'themeProvider',
+        isAutoDispose: true,
+        dependencies: null,
+        $allTransitiveDependencies: null,
+      );
+
+  @override
+  String debugGetCreateSourceHash() => _$themeNotifierHash();
+
+  @$internal
+  @override
+  ThemeNotifier create() => ThemeNotifier();
+
+  /// {@macro riverpod.override_with_value}
+  Override overrideWithValue(ThemeMode value) {
+    return $ProviderOverride(
+      origin: this,
+      providerOverride: $SyncValueProvider<ThemeMode>(value),
+    );
+  }
+}
+
+String _$themeNotifierHash() => r'060f7d104905995da8c785d2f50f15a4db2d7022';
+
+abstract class _$ThemeNotifier extends $Notifier<ThemeMode> {
+  ThemeMode build();
+  @$mustCallSuper
+  @override
+  void runBuild() {
+    final ref = this.ref as $Ref<ThemeMode, ThemeMode>;
+    final element =
+        ref.element
+            as $ClassProviderElement<
+              AnyNotifier<ThemeMode, ThemeMode>,
+              ThemeMode,
+              Object?,
+              Object?
+            >;
+    element.handleCreate(ref, build);
+  }
+}

lib/l10n/app_de.arb

@@ -1,4 +1,27 @@
 {
   "@@locale": "de",
-  "appTitle": "HouseHoldKeaper"
+  "appTitle": "HouseHoldKeaper",
+  "tabHome": "\u00dcbersicht",
+  "tabRooms": "R\u00e4ume",
+  "tabSettings": "Einstellungen",
+  "homeEmptyTitle": "Noch nichts zu tun!",
+  "homeEmptyMessage": "Lege zuerst einen Raum an, um Aufgaben zu planen.",
+  "homeEmptyAction": "Raum erstellen",
+  "roomsEmptyTitle": "Hier ist noch alles leer!",
+  "roomsEmptyMessage": "Erstelle deinen ersten Raum, um loszulegen.",
+  "roomsEmptyAction": "Raum erstellen",
+  "settingsSectionAppearance": "Darstellung",
+  "settingsThemeLabel": "Farbschema",
+  "themeSystem": "System",
+  "themeLight": "Hell",
+  "themeDark": "Dunkel",
+  "settingsSectionAbout": "\u00dcber",
+  "aboutAppName": "HouseHoldKeaper",
+  "aboutTagline": "Dein Haushalt, entspannt organisiert.",
+  "aboutVersion": "Version {version}",
+  "@aboutVersion": {
+    "placeholders": {
+      "version": { "type": "String" }
+    }
+  }
 }

lib/l10n/app_localizations.dart

@@ -0,0 +1,242 @@
+import 'dart:async';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/widgets.dart';
+import 'package:flutter_localizations/flutter_localizations.dart';
+import 'package:intl/intl.dart' as intl;
+
+import 'app_localizations_de.dart';
+
+// ignore_for_file: type=lint
+
+/// Callers can lookup localized strings with an instance of AppLocalizations
+/// returned by `AppLocalizations.of(context)`.
+///
+/// Applications need to include `AppLocalizations.delegate()` in their app's
+/// `localizationDelegates` list, and the locales they support in the app's
+/// `supportedLocales` list. For example:
+///
+/// ```dart
+/// import 'l10n/app_localizations.dart';
+///
+/// return MaterialApp(
+///   localizationsDelegates: AppLocalizations.localizationsDelegates,
+///   supportedLocales: AppLocalizations.supportedLocales,
+///   home: MyApplicationHome(),
+/// );
+/// ```
+///
+/// ## Update pubspec.yaml
+///
+/// Please make sure to update your pubspec.yaml to include the following
+/// packages:
+///
+/// ```yaml
+/// dependencies:
+///   # Internationalization support.
+///   flutter_localizations:
+///     sdk: flutter
+///   intl: any # Use the pinned version from flutter_localizations
+///
+///   # Rest of dependencies
+/// ```
+///
+/// ## iOS Applications
+///
+/// iOS applications define key application metadata, including supported
+/// locales, in an Info.plist file that is built into the application bundle.
+/// To configure the locales supported by your app, you’ll need to edit this
+/// file.
+///
+/// First, open your project’s ios/Runner.xcworkspace Xcode workspace file.
+/// Then, in the Project Navigator, open the Info.plist file under the Runner
+/// project’s Runner folder.
+///
+/// Next, select the Information Property List item, select Add Item from the
+/// Editor menu, then select Localizations from the pop-up menu.
+///
+/// Select and expand the newly-created Localizations item then, for each
+/// locale your application supports, add a new item and select the locale
+/// you wish to add from the pop-up menu in the Value field. This list should
+/// be consistent with the languages listed in the AppLocalizations.supportedLocales
+/// property.
+abstract class AppLocalizations {
+  AppLocalizations(String locale)
+    : localeName = intl.Intl.canonicalizedLocale(locale.toString());
+
+  final String localeName;
+
+  static AppLocalizations of(BuildContext context) {
+    return Localizations.of<AppLocalizations>(context, AppLocalizations)!;
+  }
+
+  static const LocalizationsDelegate<AppLocalizations> delegate =
+      _AppLocalizationsDelegate();
+
+  /// A list of this localizations delegate along with the default localizations
+  /// delegates.
+  ///
+  /// Returns a list of localizations delegates containing this delegate along with
+  /// GlobalMaterialLocalizations.delegate, GlobalCupertinoLocalizations.delegate,
+  /// and GlobalWidgetsLocalizations.delegate.
+  ///
+  /// Additional delegates can be added by appending to this list in
+  /// MaterialApp. This list does not have to be used at all if a custom list
+  /// of delegates is preferred or required.
+  static const List<LocalizationsDelegate<dynamic>> localizationsDelegates =
+      <LocalizationsDelegate<dynamic>>[
+        delegate,
+        GlobalMaterialLocalizations.delegate,
+        GlobalCupertinoLocalizations.delegate,
+        GlobalWidgetsLocalizations.delegate,
+      ];
+
+  /// A list of this localizations delegate's supported locales.
+  static const List<Locale> supportedLocales = <Locale>[Locale('de')];
+
+  /// No description provided for @appTitle.
+  ///
+  /// In de, this message translates to:
+  /// **'HouseHoldKeaper'**
+  String get appTitle;
+
+  /// No description provided for @tabHome.
+  ///
+  /// In de, this message translates to:
+  /// **'Übersicht'**
+  String get tabHome;
+
+  /// No description provided for @tabRooms.
+  ///
+  /// In de, this message translates to:
+  /// **'Räume'**
+  String get tabRooms;
+
+  /// No description provided for @tabSettings.
+  ///
+  /// In de, this message translates to:
+  /// **'Einstellungen'**
+  String get tabSettings;
+
+  /// No description provided for @homeEmptyTitle.
+  ///
+  /// In de, this message translates to:
+  /// **'Noch nichts zu tun!'**
+  String get homeEmptyTitle;
+
+  /// No description provided for @homeEmptyMessage.
+  ///
+  /// In de, this message translates to:
+  /// **'Lege zuerst einen Raum an, um Aufgaben zu planen.'**
+  String get homeEmptyMessage;
+
+  /// No description provided for @homeEmptyAction.
+  ///
+  /// In de, this message translates to:
+  /// **'Raum erstellen'**
+  String get homeEmptyAction;
+
+  /// No description provided for @roomsEmptyTitle.
+  ///
+  /// In de, this message translates to:
+  /// **'Hier ist noch alles leer!'**
+  String get roomsEmptyTitle;
+
+  /// No description provided for @roomsEmptyMessage.
+  ///
+  /// In de, this message translates to:
+  /// **'Erstelle deinen ersten Raum, um loszulegen.'**
+  String get roomsEmptyMessage;
+
+  /// No description provided for @roomsEmptyAction.
+  ///
+  /// In de, this message translates to:
+  /// **'Raum erstellen'**
+  String get roomsEmptyAction;
+
+  /// No description provided for @settingsSectionAppearance.
+  ///
+  /// In de, this message translates to:
+  /// **'Darstellung'**
+  String get settingsSectionAppearance;
+
+  /// No description provided for @settingsThemeLabel.
+  ///
+  /// In de, this message translates to:
+  /// **'Farbschema'**
+  String get settingsThemeLabel;
+
+  /// No description provided for @themeSystem.
+  ///
+  /// In de, this message translates to:
+  /// **'System'**
+  String get themeSystem;
+
+  /// No description provided for @themeLight.
+  ///
+  /// In de, this message translates to:
+  /// **'Hell'**
+  String get themeLight;
+
+  /// No description provided for @themeDark.
+  ///
+  /// In de, this message translates to:
+  /// **'Dunkel'**
+  String get themeDark;
+
+  /// No description provided for @settingsSectionAbout.
+  ///
+  /// In de, this message translates to:
+  /// **'Über'**
+  String get settingsSectionAbout;
+
+  /// No description provided for @aboutAppName.
+  ///
+  /// In de, this message translates to:
+  /// **'HouseHoldKeaper'**
+  String get aboutAppName;
+
+  /// No description provided for @aboutTagline.
+  ///
+  /// In de, this message translates to:
+  /// **'Dein Haushalt, entspannt organisiert.'**
+  String get aboutTagline;
+
+  /// No description provided for @aboutVersion.
+  ///
+  /// In de, this message translates to:
+  /// **'Version {version}'**
+  String aboutVersion(String version);
+}
+
+class _AppLocalizationsDelegate
+    extends LocalizationsDelegate<AppLocalizations> {
+  const _AppLocalizationsDelegate();
+
+  @override
+  Future<AppLocalizations> load(Locale locale) {
+    return SynchronousFuture<AppLocalizations>(lookupAppLocalizations(locale));
+  }
+
+  @override
+  bool isSupported(Locale locale) =>
+      <String>['de'].contains(locale.languageCode);
+
+  @override
+  bool shouldReload(_AppLocalizationsDelegate old) => false;
+}
+
+AppLocalizations lookupAppLocalizations(Locale locale) {
+  // Lookup logic when only language code is specified.
+  switch (locale.languageCode) {
+    case 'de':
+      return AppLocalizationsDe();
+  }
+
+  throw FlutterError(
+    'AppLocalizations.delegate failed to load unsupported locale "$locale". This is likely '
+    'an issue with the localizations generation tool. Please file an issue '
+    'on GitHub with a reproducible sample app and the gen-l10n configuration '
+    'that was used.',
+  );
+}

lib/l10n/app_localizations_de.dart

@@ -0,0 +1,70 @@
+// ignore: unused_import
+import 'package:intl/intl.dart' as intl;
+import 'app_localizations.dart';
+
+// ignore_for_file: type=lint
+
+/// The translations for German (`de`).
+class AppLocalizationsDe extends AppLocalizations {
+  AppLocalizationsDe([String locale = 'de']) : super(locale);
+
+  @override
+  String get appTitle => 'HouseHoldKeaper';
+
+  @override
+  String get tabHome => 'Übersicht';
+
+  @override
+  String get tabRooms => 'Räume';
+
+  @override
+  String get tabSettings => 'Einstellungen';
+
+  @override
+  String get homeEmptyTitle => 'Noch nichts zu tun!';
+
+  @override
+  String get homeEmptyMessage =>
+      'Lege zuerst einen Raum an, um Aufgaben zu planen.';
+
+  @override
+  String get homeEmptyAction => 'Raum erstellen';
+
+  @override
+  String get roomsEmptyTitle => 'Hier ist noch alles leer!';
+
+  @override
+  String get roomsEmptyMessage => 'Erstelle deinen ersten Raum, um loszulegen.';
+
+  @override
+  String get roomsEmptyAction => 'Raum erstellen';
+
+  @override
+  String get settingsSectionAppearance => 'Darstellung';
+
+  @override
+  String get settingsThemeLabel => 'Farbschema';
+
+  @override
+  String get themeSystem => 'System';
+
+  @override
+  String get themeLight => 'Hell';
+
+  @override
+  String get themeDark => 'Dunkel';
+
+  @override
+  String get settingsSectionAbout => 'Über';
+
+  @override
+  String get aboutAppName => 'HouseHoldKeaper';
+
+  @override
+  String get aboutTagline => 'Dein Haushalt, entspannt organisiert.';
+
+  @override
+  String aboutVersion(String version) {
+    return 'Version $version';
+  }
+}

lib/main.dart

@@ -1,122 +1,6 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 void main() {
-  runApp(const MyApp());
-}
-
-class MyApp extends StatelessWidget {
-  const MyApp({super.key});
-
-  // This widget is the root of your application.
-  @override
-  Widget build(BuildContext context) {
-    return MaterialApp(
-      title: 'Flutter Demo',
-      theme: ThemeData(
-        // This is the theme of your application.
-        //
-        // TRY THIS: Try running your application with "flutter run". You'll see
-        // the application has a purple toolbar. Then, without quitting the app,
-        // try changing the seedColor in the colorScheme below to Colors.green
-        // and then invoke "hot reload" (save your changes or press the "hot
-        // reload" button in a Flutter-supported IDE, or press "r" if you used
-        // the command line to start the app).
-        //
-        // Notice that the counter didn't reset back to zero; the application
-        // state is not lost during the reload. To reset the state, use hot
-        // restart instead.
-        //
-        // This works for code too, not just values: Most code changes can be
-        // tested with just a hot reload.
-        colorScheme: .fromSeed(seedColor: Colors.deepPurple),
-      ),
-      home: const MyHomePage(title: 'Flutter Demo Home Page'),
-    );
-  }
-}
-
-class MyHomePage extends StatefulWidget {
-  const MyHomePage({super.key, required this.title});
-
-  // This widget is the home page of your application. It is stateful, meaning
-  // that it has a State object (defined below) that contains fields that affect
-  // how it looks.
-
-  // This class is the configuration for the state. It holds the values (in this
-  // case the title) provided by the parent (in this case the App widget) and
-  // used by the build method of the State. Fields in a Widget subclass are
-  // always marked "final".
-
-  final String title;
-
-  @override
-  State<MyHomePage> createState() => _MyHomePageState();
-}
-
-class _MyHomePageState extends State<MyHomePage> {
-  int _counter = 0;
-
-  void _incrementCounter() {
-    setState(() {
-      // This call to setState tells the Flutter framework that something has
-      // changed in this State, which causes it to rerun the build method below
-      // so that the display can reflect the updated values. If we changed
-      // _counter without calling setState(), then the build method would not be
-      // called again, and so nothing would appear to happen.
-      _counter++;
-    });
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    // This method is rerun every time setState is called, for instance as done
-    // by the _incrementCounter method above.
-    //
-    // The Flutter framework has been optimized to make rerunning build methods
-    // fast, so that you can just rebuild anything that needs updating rather
-    // than having to individually change instances of widgets.
-    return Scaffold(
-      appBar: AppBar(
-        // TRY THIS: Try changing the color here to a specific color (to
-        // Colors.amber, perhaps?) and trigger a hot reload to see the AppBar
-        // change color while the other colors stay the same.
-        backgroundColor: Theme.of(context).colorScheme.inversePrimary,
-        // Here we take the value from the MyHomePage object that was created by
-        // the App.build method, and use it to set our appbar title.
-        title: Text(widget.title),
-      ),
-      body: Center(
-        // Center is a layout widget. It takes a single child and positions it
-        // in the middle of the parent.
-        child: Column(
-          // Column is also a layout widget. It takes a list of children and
-          // arranges them vertically. By default, it sizes itself to fit its
-          // children horizontally, and tries to be as tall as its parent.
-          //
-          // Column has various properties to control how it sizes itself and
-          // how it positions its children. Here we use mainAxisAlignment to
-          // center the children vertically; the main axis here is the vertical
-          // axis because Columns are vertical (the cross axis would be
-          // horizontal).
-          //
-          // TRY THIS: Invoke "debug painting" (choose the "Toggle Debug Paint"
-          // action in the IDE, or press "p" in the console), to see the
-          // wireframe for each widget.
-          mainAxisAlignment: .center,
-          children: [
-            const Text('You have pushed the button this many times:'),
-            Text(
-              '$_counter',
-              style: Theme.of(context).textTheme.headlineMedium,
-            ),
-          ],
-        ),
-      ),
-      floatingActionButton: FloatingActionButton(
-        onPressed: _incrementCounter,
-        tooltip: 'Increment',
-        child: const Icon(Icons.add),
-      ),
-    );
-  }
+  runApp(const ProviderScope(child: MaterialApp(home: Scaffold())));
 }

test/core/database/database_test.dart

@@ -0,0 +1,31 @@
+import 'package:drift/native.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:household_keeper/core/database/database.dart';
+
+void main() {
+  group('AppDatabase', () {
+    late AppDatabase db;
+
+    setUp(() {
+      db = AppDatabase(NativeDatabase.memory());
+    });
+
+    tearDown(() async {
+      await db.close();
+    });
+
+    test('opens successfully with in-memory executor', () {
+      expect(db, isNotNull);
+    });
+
+    test('has schemaVersion 1', () {
+      expect(db.schemaVersion, equals(1));
+    });
+
+    test('can be closed without error', () async {
+      await db.close();
+      // If we reach here, close succeeded. Re-create for tearDown.
+      db = AppDatabase(NativeDatabase.memory());
+    });
+  });
+}

test/core/theme/color_scheme_test.dart

@@ -0,0 +1,45 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:household_keeper/core/theme/app_theme.dart';
+
+void main() {
+  group('AppTheme ColorScheme', () {
+    test('lightTheme has Brightness.light', () {
+      final theme = AppTheme.lightTheme();
+      expect(theme.colorScheme.brightness, equals(Brightness.light));
+    });
+
+    test('darkTheme has Brightness.dark', () {
+      final theme = AppTheme.darkTheme();
+      expect(theme.colorScheme.brightness, equals(Brightness.dark));
+    });
+
+    test('both themes use sage green seed (primary in green hue range)', () {
+      final lightPrimary = HSLColor.fromColor(
+        AppTheme.lightTheme().colorScheme.primary,
+      );
+      final darkPrimary = HSLColor.fromColor(
+        AppTheme.darkTheme().colorScheme.primary,
+      );
+
+      // Sage green hue is approximately 100-150 degrees
+      expect(lightPrimary.hue, inInclusiveRange(80, 160));
+      expect(darkPrimary.hue, inInclusiveRange(80, 160));
+    });
+
+    test('light surface color is warm stone (0xFFF5F0E8)', () {
+      final theme = AppTheme.lightTheme();
+      expect(theme.colorScheme.surface, equals(const Color(0xFFF5F0E8)));
+    });
+
+    test('dark surface color is warm charcoal (0xFF2A2520), not cold gray', () {
+      final theme = AppTheme.darkTheme();
+      expect(theme.colorScheme.surface, equals(const Color(0xFF2A2520)));
+    });
+
+    test('both themes use Material 3', () {
+      expect(AppTheme.lightTheme().useMaterial3, isTrue);
+      expect(AppTheme.darkTheme().useMaterial3, isTrue);
+    });
+  });
+}

test/core/theme/theme_test.dart

@@ -0,0 +1,41 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+import 'package:household_keeper/core/theme/theme_provider.dart';
+
+void main() {
+  group('ThemeNotifier', () {
+    setUp(() {
+      SharedPreferences.setMockInitialValues({});
+    });
+
+    test('defaults to ThemeMode.system', () {
+      final container = ProviderContainer();
+      addTearDown(container.dispose);
+
+      final themeMode = container.read(themeProvider);
+      expect(themeMode, equals(ThemeMode.system));
+    });
+
+    test('setThemeMode(dark) updates state to dark', () async {
+      final container = ProviderContainer();
+      addTearDown(container.dispose);
+
+      await container.read(themeProvider.notifier).setThemeMode(
+        ThemeMode.dark,
+      );
+      expect(container.read(themeProvider), equals(ThemeMode.dark));
+    });
+
+    test('setThemeMode(light) updates state to light', () async {
+      final container = ProviderContainer();
+      addTearDown(container.dispose);
+
+      await container.read(themeProvider.notifier).setThemeMode(
+        ThemeMode.light,
+      );
+      expect(container.read(themeProvider), equals(ThemeMode.light));
+    });
+  });
+}

test/l10n/localization_test.dart

@@ -0,0 +1,56 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:household_keeper/l10n/app_localizations.dart';
+
+void main() {
+  group('AppLocalizations (German)', () {
+    late AppLocalizations l10n;
+
+    testWidgets('loads German localization and displays tabHome',
+        (tester) async {
+      late AppLocalizations capturedL10n;
+
+      await tester.pumpWidget(
+        MaterialApp(
+          localizationsDelegates: AppLocalizations.localizationsDelegates,
+          supportedLocales: const [Locale('de')],
+          locale: const Locale('de'),
+          home: Builder(
+            builder: (context) {
+              capturedL10n = AppLocalizations.of(context);
+              return Text(capturedL10n.tabHome);
+            },
+          ),
+        ),
+      );
+
+      await tester.pumpAndSettle();
+
+      // Verify the rendered text contains the expected German string
+      expect(find.text('\u00dcbersicht'), findsOneWidget);
+    });
+
+    testWidgets('all critical keys are non-empty', (tester) async {
+      await tester.pumpWidget(
+        MaterialApp(
+          localizationsDelegates: AppLocalizations.localizationsDelegates,
+          supportedLocales: const [Locale('de')],
+          locale: const Locale('de'),
+          home: Builder(
+            builder: (context) {
+              l10n = AppLocalizations.of(context);
+              return const SizedBox.shrink();
+            },
+          ),
+        ),
+      );
+
+      await tester.pumpAndSettle();
+
+      expect(l10n.appTitle, isNotEmpty);
+      expect(l10n.tabHome, isNotEmpty);
+      expect(l10n.tabRooms, isNotEmpty);
+      expect(l10n.tabSettings, isNotEmpty);
+    });
+  });
+}

test/widget_test.dart

@@ -1,30 +0,0 @@
-// This is a basic Flutter widget test.
-//
-// To perform an interaction with a widget in your test, use the WidgetTester
-// utility in the flutter_test package. For example, you can send tap and scroll
-// gestures. You can also use WidgetTester to find child widgets in the widget
-// tree, read text, and verify that the values of widget properties are correct.
-
-import 'package:flutter/material.dart';
-import 'package:flutter_test/flutter_test.dart';
-
-import 'package:household_keeper/main.dart';
-
-void main() {
-  testWidgets('Counter increments smoke test', (WidgetTester tester) async {
-    // Build our app and trigger a frame.
-    await tester.pumpWidget(const MyApp());
-
-    // Verify that our counter starts at 0.
-    expect(find.text('0'), findsOneWidget);
-    expect(find.text('1'), findsNothing);
-
-    // Tap the '+' icon and trigger a frame.
-    await tester.tap(find.byIcon(Icons.add));
-    await tester.pump();
-
-    // Verify that our counter has incremented.
-    expect(find.text('0'), findsNothing);
-    expect(find.text('1'), findsOneWidget);
-  });
-}