test: 补充组件交互用例，覆盖率提升至 80%+

src/renderer/src/__tests__/App.test.tsx

@@ -1,7 +1,27 @@
-import { describe, it, expect } from 'vitest'
+import { describe, it, expect, beforeEach } from 'vitest'
-import { render, screen } from '@testing-library/react'
+import { render, screen, fireEvent } from '@testing-library/react'
 import App from '../App'
 
+function mockApi(overrides?: Partial<typeof window.api>): typeof window.api {
+  const base = {
+    openFile: async () => ({
+      path: '/tmp/a.txt',
+      name: 'a.txt',
+      text: 'line1\nline2',
+      encoding: 'UTF-8'
+    }),
+    decodeBuffer: async () => ({ text: 'line1\nline2', encoding: 'UTF-8' }),
+    saveReport: async () => ({ ok: false, path: null }),
+    showInFolder: async () => true,
+    setClipboard: async () => true
+  }
+  return { ...base, ...overrides } as typeof window.api
+}
+
+beforeEach(() => {
+  window.api = mockApi()
+})
+
 describe('App - 初始空态', () => {
   it('渲染应用名称 DiffLens', () => {
     render(<App />)
@@ -19,3 +39,21 @@ describe('App - 初始空态', () => {
     expect(screen.queryByText('导出报告')).not.toBeInTheDocument()
   })
 })
+
+describe('App - 加载文件后的非空态', () => {
+  it('打开文件后渲染对比视图与导出入口，并显示文件内容', async () => {
+    render(<App />)
+    fireEvent.click(screen.getByText('打开左侧'))
+
+    expect(await screen.findByText('导出报告')).toBeInTheDocument()
+    // 被对比的内容渲染（此处与空文件对比，内容出现在面板中）
+    expect((await screen.findAllByText(/line1/)).length).toBeGreaterThan(0)
+    expect(screen.getAllByText('a.txt').length).toBeGreaterThan(0)
+  })
+
+  it('右侧打开文件后可导出报告', async () => {
+    render(<App />)
+    fireEvent.click(screen.getByText('打开右侧'))
+    expect(await screen.findByText('导出报告')).toBeInTheDocument()
+  })
+})

src/renderer/src/components/ContextMenu.test.tsx

@@ -0,0 +1,42 @@
+import { describe, it, expect, vi } from 'vitest'
+import { render, screen, fireEvent } from '@testing-library/react'
+import ContextMenu, { type ContextMenuItem } from './ContextMenu'
+
+describe('ContextMenu', () => {
+  it('渲染菜单项并触行动作后关闭', () => {
+    const action = vi.fn()
+    const onClose = vi.fn()
+    const items: ContextMenuItem[] = [{ label: '复制此行内容', action }]
+    const { container } = render(
+      <ContextMenu x={10} y={10} items={items} onClose={onClose} />
+    )
+    fireEvent.click(screen.getByText('复制此行内容'))
+    expect(action).toHaveBeenCalledTimes(1)
+    expect(onClose).toHaveBeenCalled()
+    expect(container.firstChild).toBeTruthy()
+  })
+
+  it('禁用项不触行动作', () => {
+    const action = vi.fn()
+    const onClose = vi.fn()
+    const items: ContextMenuItem[] = [
+      { label: '在文件夹中显示', disabled: true, action },
+      { label: '复制文件名', action }
+    ]
+    render(<ContextMenu x={10} y={10} items={items} onClose={onClose} />)
+    fireEvent.click(screen.getByText('在文件夹中显示'))
+    expect(action).not.toHaveBeenCalled()
+    expect(onClose).not.toHaveBeenCalled()
+  })
+
+  it('点击遮罩层触发关闭', () => {
+    const onClose = vi.fn()
+    const { container } = render(
+      <ContextMenu x={10} y={10} items={[]} onClose={onClose} />
+    )
+    const backdrop = container.querySelector('.ctx-backdrop')
+    expect(backdrop).not.toBeNull()
+    fireEvent.mouseDown(backdrop as Element)
+    expect(onClose).toHaveBeenCalled()
+  })
+})

src/renderer/src/components/DiffView.test.tsx

@@ -0,0 +1,60 @@
+import { describe, it, expect, vi, beforeAll } from 'vitest'
+import { render, screen } from '@testing-library/react'
+import DiffView from './DiffView'
+import type { DiffRow } from '../diff/diffEngine'
+
+beforeAll(() => {
+  // jsdom 未实现 scrollIntoView，测试里打桩
+  Element.prototype.scrollIntoView = vi.fn()
+})
+
+function makeDiff(activeRowId: string | null): void {
+  const rows: DiffRow[] = [
+    {
+      id: 'r0',
+      rowKind: 'unchanged',
+      isChanged: false,
+      left: { lineNo: 1, text: 'hello', segs: null },
+      right: { lineNo: 1, text: 'hello', segs: null }
+    },
+    {
+      id: 'r1',
+      rowKind: 'added',
+      isChanged: true,
+      left: { lineNo: null, text: null, segs: null },
+      right: { lineNo: 2, text: 'world', segs: null }
+    }
+  ]
+  render(
+    <DiffView
+      diff={{ rows, summary: { changedLines: 1, inserted: 1, deleted: 0, modified: 0 } }}
+      leftMeta={{ name: 'a.txt', encoding: 'UTF-8' }}
+      rightMeta={{ name: 'b.txt', encoding: 'GBK' }}
+      activeRowId={activeRowId}
+      onOpen={vi.fn()}
+      onRowContext={vi.fn()}
+    />
+  )
+}
+
+describe('DiffView', () => {
+  it('渲染左右文件名与同/新增行内容', () => {
+    makeDiff(null)
+    expect(screen.getByText('a.txt')).toBeInTheDocument()
+    expect(screen.getByText('b.txt')).toBeInTheDocument()
+    expect(screen.getAllByText('hello').length).toBeGreaterThanOrEqual(2)
+    expect(screen.getAllByText('world').length).toBeGreaterThan(0)
+  })
+
+  it('渲染行号', () => {
+    makeDiff(null)
+    // 两栏各自渲染行号 1，总共应有多个
+    expect(screen.getAllByText('1').length).toBeGreaterThan(0)
+    expect(screen.getAllByText('2').length).toBeGreaterThan(0)
+  })
+
+  it('设置活动行时调用 scrollIntoView 定位', () => {
+    makeDiff('r1')
+    expect(Element.prototype.scrollIntoView).toHaveBeenCalled()
+  })
+})

src/renderer/src/components/Toolbar.test.tsx

@@ -0,0 +1,65 @@
+import { describe, it, expect, vi } from 'vitest'
+import { render, screen, fireEvent } from '@testing-library/react'
+import Toolbar from './Toolbar'
+import { DiffSummary } from '../diff/diffEngine'
+
+const summary: DiffSummary = { changedLines: 3, inserted: 1, deleted: 1, modified: 1 }
+
+function setup(extra?: { canExport?: boolean }) {
+  const onOptionsChange = vi.fn()
+  const onNav = vi.fn()
+  const onExport = vi.fn()
+  const utils = render(
+    <Toolbar
+      options={{ trimWhitespace: false, ignoreCase: false }}
+      onOptionsChange={onOptionsChange}
+      summary={summary}
+      navIndex={0}
+      navCount={3}
+      onNav={onNav}
+      onExport={onExport}
+      canExport={extra?.canExport ?? true}
+    />
+  )
+  return { onOptionsChange, onNav, onExport, ...utils }
+}
+
+describe('Toolbar', () => {
+  it('渲染差异统计徽章', () => {
+    setup()
+    expect(screen.getByText('+1')).toBeInTheDocument()
+    expect(screen.getByText('−1')).toBeInTheDocument()
+    expect(screen.getByText('~1')).toBeInTheDocument()
+  })
+
+  it('切换忽略大小写触发 onOptionsChange', () => {
+    const { onOptionsChange } = setup()
+    fireEvent.click(screen.getByLabelText('忽略大小写'))
+    expect(onOptionsChange).toHaveBeenCalledWith({ trimWhitespace: false, ignoreCase: true })
+  })
+
+  it('切换忽略行首尾空白触发 onOptionsChange', () => {
+    const { onOptionsChange } = setup()
+    fireEvent.click(screen.getByLabelText('忽略行首尾空白'))
+    expect(onOptionsChange).toHaveBeenCalledWith({ trimWhitespace: true, ignoreCase: false })
+  })
+
+  it('点击下一处差异调用 onNav(1)', () => {
+    const { onNav } = setup()
+    fireEvent.click(screen.getByTitle('下一处差异'))
+    expect(onNav).toHaveBeenCalledWith(1)
+  })
+
+  it('点击上一处差异调用 onNav(-1)', () => {
+    const { onNav } = setup()
+    fireEvent.click(screen.getByTitle('上一处差异'))
+    expect(onNav).toHaveBeenCalledWith(-1)
+  })
+
+  it('导出菜单选择 HTML 触发 onExport("html")', () => {
+    const { onExport } = setup()
+    fireEvent.click(screen.getByText('导出报告'))
+    fireEvent.click(screen.getByText('HTML 报告'))
+    expect(onExport).toHaveBeenCalledWith('html')
+  })
+})