add some props an features

test/bauteil_bestand_test.dart

@@ -16,6 +16,7 @@ import 'package:ertl_filament_verwaltung/services/bauteil_photo_service.dart';
 import 'package:ertl_filament_verwaltung/services/get_storage_services.dart';
 import 'package:ertl_filament_verwaltung/theme/app_theme.dart';
 import 'package:ertl_filament_verwaltung/widgets/bauteil_card.dart';
+import 'package:ertl_filament_verwaltung/widgets/bauteil_filament_auswahl.dart';
 import 'package:ertl_filament_verwaltung/widgets/bauteil_photo.dart';
 
 import 'helpers/memory_storage_service.dart';
@@ -123,6 +124,53 @@ void main() {
     home.filamente.firstWhere((item) => item.filamentId == id),
   )!;
 
+  testWidgets('Dropdown adds only selected filaments and supports removal', (
+    tester,
+  ) async {
+    await tester.pumpWidget(
+      GetMaterialApp(
+        theme: AppTheme.light,
+        home: Scaffold(
+          body: SingleChildScrollView(
+            child: BauteilFilamentAuswahl(controller: controller),
+          ),
+        ),
+      ),
+    );
+    expect(find.byKey(const ValueKey('filament-a')), findsNothing);
+    expect(find.byKey(const ValueKey('filament-b')), findsNothing);
+
+    Future<void> add(String id) async {
+      await tester.tap(find.byType(DropdownButtonFormField<String>));
+      await tester.pumpAndSettle();
+      await tester.tap(find.text(controller.filamentLabel(id)).last);
+      await tester.pumpAndSettle();
+    }
+
+    await add('a');
+    controller.verbrauchController('a').text = '25';
+    expect(find.byKey(const ValueKey('filament-a')), findsOneWidget);
+    expect(find.byKey(const ValueKey('filament-b')), findsNothing);
+    expect(controller.selectedFilamente.keys, ['a']);
+
+    await add('b');
+    expect(find.byType(DropdownButtonFormField<String>), findsNothing);
+    expect(find.byKey(const ValueKey('filament-b')), findsOneWidget);
+    await tester.tap(find.byTooltip('Filament entfernen').first);
+    await tester.pumpAndSettle();
+    expect(find.byKey(const ValueKey('filament-a')), findsNothing);
+    expect(controller.selectedFilamente.keys, ['b']);
+
+    await add('a');
+    expect(controller.verbrauchController('a').text, '25');
+    controller.resetForm();
+    await tester.pumpAndSettle();
+    expect(find.byKey(const ValueKey('filament-a')), findsNothing);
+    expect(find.byKey(const ValueKey('filament-b')), findsNothing);
+    expect(find.byType(DropdownButtonFormField<String>), findsOneWidget);
+    expect(tester.takeException(), isNull);
+  });
+
   test(
     'Legacy records retain unknown usage and old weight units are supported',
     () {