修复用户端个人头像展示

apps/user_app/test/ui/profile_avatar_test.dart

@@ -0,0 +1,71 @@
+// 功能描述：验证用户头像的真实图片、空值占位和加载失败回退状态。
+// 版本：1.0.0
+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:user_app/data/services/api_client.dart';
+import 'package:user_app/ui/features/profile/profile_avatar.dart';
+
+/// 验证头像组件在不同图片状态下保持可用。
+void main() {
+  /// 构建统一头像测试宿主。
+  Widget testHost({
+    required String name,
+    required Uint8List? imageBytes,
+  }) => MaterialApp(
+    home: Scaffold(
+      body: ProfileAvatar(
+        name: name,
+        imageBytes: imageBytes,
+      ),
+    ),
+  );
+
+  testWidgets('有头像时使用圆形裁剪图片', (tester) async {
+    final imageBytes = Uint8List.fromList(
+      base64Decode(
+        'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+M/wHwAF/gL+X8l7WQAAAABJRU5ErkJggg==',
+      ),
+    );
+    await tester.pumpWidget(
+      testHost(
+        name: 'cyyy',
+        imageBytes: imageBytes,
+      ),
+    );
+    await tester.pumpAndSettle();
+
+    final image = tester.widget<Image>(find.byKey(const Key('profile-avatar-image')));
+    expect(image.fit, BoxFit.cover);
+    expect(image.image, isA<MemoryImage>());
+  });
+
+  testWidgets('头像为空时显示用户名首字母', (tester) async {
+    await tester.pumpWidget(testHost(name: 'cyyy', imageBytes: null));
+
+    expect(find.text('c'), findsOneWidget);
+    expect(find.byKey(const Key('profile-avatar-image')), findsNothing);
+  });
+
+  testWidgets('头像加载失败时回退用户名首字母', (tester) async {
+    await tester.pumpWidget(
+      testHost(
+        name: 'cyyy',
+        imageBytes: Uint8List.fromList(const [0]),
+      ),
+    );
+    await tester.pumpAndSettle();
+
+    expect(find.text('c'), findsOneWidget);
+  });
+
+  test('头像接口失败时安全返回空值', () async {
+    final result = await loadProfileAvatarSafely(
+      () => throw const ApiException(500, '头像加载失败'),
+    );
+
+    expect(result, isNull);
+  });
+}