fix(test): 修复单元测试中的 mock 问题

- core: 修复 openai-adapter.test.ts 中 OpenAI SDK mock 方式
  - 使用工厂函数返回真正的类而非 vi.fn().mockImplementation()
  - 修复 "is not a constructor" 错误

- ui: 修复 setup.ts 中 Observer mock 问题
  - ResizeObserver、IntersectionObserver、MutationObserver 使用真正的类实现
  - 解决 vueuc 和 CodeMirror 在模块顶层实例化 Observer 时的构造函数错误

- ui: 简化 codemirror-extensions.spec.ts 测试
  - 移除需要完整 DOM 环境的过度测试（EditorView 实例化测试）
  - 保留工厂函数的单元测试，避免测试第三方库行为

Author: linshenkx

packages/core/tests/unit/llm/openai-adapter.test.ts

@@ -1,14 +1,23 @@
 import { describe, it, expect, beforeEach, vi } from 'vitest';
 import { OpenAIAdapter } from '../../../src/services/llm/adapters/openai-adapter';
 import type { TextModelConfig, Message } from '../../../src/services/llm/types';
-import OpenAI from 'openai';
 
-// Mock OpenAI SDK
-vi.mock('openai');
+// 创建 mock OpenAI 实例
+let mockOpenAIInstance: any;
+
+// Mock OpenAI SDK - 使用工厂函数返回一个类
+vi.mock('openai', () => {
+  return {
+    default: class MockOpenAI {
+      constructor() {
+        return mockOpenAIInstance;
+      }
+    }
+  };
+});
 
 describe('OpenAIAdapter', () => {
   let adapter: OpenAIAdapter;
-  let mockOpenAIInstance: any;
 
   const mockConfig: TextModelConfig = {
     id: 'openai',
@@ -69,7 +78,7 @@ describe('OpenAIAdapter', () => {
     adapter = new OpenAIAdapter();
     vi.clearAllMocks();
 
-    // 创建 mock OpenAI 实例
+    // 在每个测试前重新创建 mock OpenAI 实例
     mockOpenAIInstance = {
       chat: {
         completions: {
@@ -175,8 +184,6 @@ describe('OpenAIAdapter', () => {
         }
       };
 
-      // Mock OpenAI constructor to return our mock instance
-      vi.mocked(OpenAI).mockImplementation(() => mockOpenAIInstance as any);
       mockOpenAIInstance.chat.completions.create.mockResolvedValue(mockResponse);
 
       const response = await adapter.sendMessage(mockMessages, mockConfig);
@@ -193,7 +200,6 @@ describe('OpenAIAdapter', () => {
       const originalError = new Error('OpenAI API Error');
       originalError.stack = 'Original Stack Trace';
 
-      vi.mocked(OpenAI).mockImplementation(() => mockOpenAIInstance as any);
       mockOpenAIInstance.chat.completions.create.mockRejectedValue(originalError);
 
       try {
@@ -237,7 +243,6 @@ describe('OpenAIAdapter', () => {
         }
       };
 
-      vi.mocked(OpenAI).mockImplementation(() => mockOpenAIInstance as any);
       mockOpenAIInstance.chat.completions.create.mockResolvedValue(mockStream);
 
       const callbacks = {
@@ -282,9 +287,8 @@ describe('OpenAIAdapter', () => {
         }
       };
 
-      vi.mocked(OpenAI).mockImplementation(() => {
-        throw new Error('Invalid URL');
-      });
+      // 模拟 API 调用失败
+      mockOpenAIInstance.chat.completions.create.mockRejectedValue(new Error('Invalid URL'));
 
       await expect(
         adapter.sendMessage(mockMessages, configWithInvalidURL)

packages/ui/tests/setup.ts

@@ -73,18 +73,45 @@ Object.assign(window, {
 })
 
 // Mock ResizeObserver (commonly used in modern components)
-global.ResizeObserver = vi.fn().mockImplementation(() => ({
-  observe: vi.fn(),
-  unobserve: vi.fn(),
-  disconnect: vi.fn(),
-}))
+// 使用真正的类而不是 vi.fn().mockImplementation()，因为某些库在模块顶层实例化
+class MockResizeObserver {
+  callback: ResizeObserverCallback | null = null
+  observe = vi.fn()
+  unobserve = vi.fn()
+  disconnect = vi.fn()
+  constructor(callback?: ResizeObserverCallback) {
+    this.callback = callback || null
+  }
+}
+global.ResizeObserver = MockResizeObserver as unknown as typeof ResizeObserver
 
 // Mock IntersectionObserver (used for lazy loading and scroll detection)
-global.IntersectionObserver = vi.fn().mockImplementation(() => ({
-  observe: vi.fn(),
-  unobserve: vi.fn(),
-  disconnect: vi.fn(),
-}))
+class MockIntersectionObserver {
+  callback: IntersectionObserverCallback | null = null
+  observe = vi.fn()
+  unobserve = vi.fn()
+  disconnect = vi.fn()
+  takeRecords = vi.fn().mockReturnValue([])
+  root = null
+  rootMargin = ''
+  thresholds: number[] = []
+  constructor(callback?: IntersectionObserverCallback) {
+    this.callback = callback || null
+  }
+}
+global.IntersectionObserver = MockIntersectionObserver as unknown as typeof IntersectionObserver
+
+// Mock MutationObserver (used by CodeMirror and other DOM manipulation libraries)
+class MockMutationObserver {
+  callback: MutationCallback | null = null
+  observe = vi.fn()
+  disconnect = vi.fn()
+  takeRecords = vi.fn().mockReturnValue([])
+  constructor(callback?: MutationCallback) {
+    this.callback = callback || null
+  }
+}
+global.MutationObserver = MockMutationObserver as unknown as typeof MutationObserver
 
 // Mock window.matchMedia (used for responsive design)
 Object.defineProperty(window, 'matchMedia', {