feat: 增加测试覆盖率并优化代码质量

test: 添加单元测试和端到端测试
refactor: 重构登录页面和上传模块
ci: 更新测试覆盖率阈值至42%
build: 添加测试相关依赖
docs: 更新测试文档
style: 修复代码格式问题

src/app/privacy/page.test.tsx

@@ -0,0 +1,47 @@
+import { render, screen } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import PrivacyPolicyPage from './page';
+
+describe('PrivacyPolicyPage', () => {
+  beforeEach(() => {
+    jest.clearAllMocks();
+  });
+
+  describe('Rendering', () => {
+    it('should render privacy policy page', () => {
+      render(<PrivacyPolicyPage />);
+      const container = screen.getByText('隐私政策').closest('div');
+      expect(container).toBeInTheDocument();
+    });
+
+    it('should render page title', () => {
+      render(<PrivacyPolicyPage />);
+      const title = screen.getByRole('heading', { level: 1 });
+      expect(title).toBeInTheDocument();
+      expect(title).toHaveTextContent('隐私政策');
+    });
+
+    it('should render introduction section', () => {
+      render(<PrivacyPolicyPage />);
+      const intro = screen.getByText('引言');
+      expect(intro).toBeInTheDocument();
+    });
+
+    it('should render information collection section', () => {
+      render(<PrivacyPolicyPage />);
+      const section = screen.getByText(/我们如何收集和使用您的个人信息/i);
+      expect(section).toBeInTheDocument();
+    });
+  });
+
+  describe('Accessibility', () => {
+    it('should have proper heading hierarchy', () => {
+      render(<PrivacyPolicyPage />);
+      const h1 = screen.getByRole('heading', { level: 1 });
+      expect(h1).toBeInTheDocument();
+      
+      const h2s = screen.getAllByRole('heading', { level: 2 });
+      expect(h2s.length).toBeGreaterThan(0);
+    });
+  });
+});