完善PR审查后出现的问题

lib/services/update_service.dart

@@ -15,7 +15,16 @@ import '../data/models/app_update_model.dart';
 import 'storage_service.dart';
 
 class UpdateService extends ChangeNotifier {
-  UpdateService._();
+  UpdateService._()
+    : _dio = Dio(_dioOptions),
+      _packageInfoProvider = PackageInfo.fromPlatform;
+
+  @visibleForTesting
+  UpdateService.test({
+    Dio? dio,
+    Future<PackageInfo> Function()? packageInfoProvider,
+  }) : _dio = dio ?? Dio(_dioOptions),
+       _packageInfoProvider = packageInfoProvider ?? PackageInfo.fromPlatform;
 
   static final UpdateService instance = UpdateService._();
 
@@ -29,15 +38,16 @@ class UpdateService extends ChangeNotifier {
     'https://www.gongyun.org/downloads.html',
   );
 
-  final Dio _dio = Dio(
-    BaseOptions(
-      connectTimeout: const Duration(seconds: 12),
-      receiveTimeout: const Duration(seconds: 20),
-      followRedirects: true,
-      responseType: ResponseType.plain,
-    ),
+  static final BaseOptions _dioOptions = BaseOptions(
+    connectTimeout: const Duration(seconds: 12),
+    receiveTimeout: const Duration(seconds: 20),
+    followRedirects: true,
+    responseType: ResponseType.plain,
   );
 
+  final Dio _dio;
+  final Future<PackageInfo> Function() _packageInfoProvider;
+
   bool _checking = false;
   AppUpdateInfo? _availableUpdate;
 
@@ -49,7 +59,7 @@ class UpdateService extends ChangeNotifier {
 
     _checking = true;
     try {
-      final current = await PackageInfo.fromPlatform();
+      final current = await _packageInfoProvider();
       final latest = await _fetchLatestRelease(currentVersion: current.version);
       if (latest == null ||
           _compareVersions(latest.version, current.version) <= 0) {