Add test for vibration setting functionality

Co-authored-by: jonasbark <1151304+jonasbark@users.noreply.github.com>

test/vibration_setting_test.dart

@@ -0,0 +1,56 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+import 'package:swift_control/utils/settings/settings.dart';
+
+void main() {
+  group('Vibration Setting Tests', () {
+    late Settings settings;
+
+    setUp(() async {
+      // Initialize SharedPreferences with in-memory storage for testing
+      SharedPreferences.setMockInitialValues({});
+      settings = Settings();
+      await settings.init();
+    });
+
+    test('Vibration setting should default to true', () {
+      expect(settings.getVibrationEnabled(), true);
+    });
+
+    test('Vibration setting should persist when set to false', () async {
+      await settings.setVibrationEnabled(false);
+      expect(settings.getVibrationEnabled(), false);
+    });
+
+    test('Vibration setting should persist when set to true', () async {
+      await settings.setVibrationEnabled(true);
+      expect(settings.getVibrationEnabled(), true);
+    });
+
+    test('Vibration setting should toggle correctly', () async {
+      // Start with default (true)
+      expect(settings.getVibrationEnabled(), true);
+      
+      // Toggle to false
+      await settings.setVibrationEnabled(false);
+      expect(settings.getVibrationEnabled(), false);
+      
+      // Toggle back to true
+      await settings.setVibrationEnabled(true);
+      expect(settings.getVibrationEnabled(), true);
+    });
+
+    test('Vibration setting should persist across Settings instances', () async {
+      // Set vibration to false
+      await settings.setVibrationEnabled(false);
+      expect(settings.getVibrationEnabled(), false);
+
+      // Create a new Settings instance
+      final newSettings = Settings();
+      await newSettings.init();
+      
+      // Should still be false
+      expect(newSettings.getVibrationEnabled(), false);
+    });
+  });
+}