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測試指南

如何測試使用 Dropup 的元件。

設定​

安裝測試相依性：

npm install -D vitest @testing-library/react @testing-library/user-event jsdom

設定 Vitest：

// vitest.config.ts
import { defineConfig } from 'vitest/config';
import react from '@vitejs/plugin-react';

export default defineConfig({
  plugins: [react()],
  test: {
    environment: 'jsdom',
    setupFiles: './src/test/setup.ts',
  },
});
// src/test/setup.ts
import '@testing-library/jest-dom';

基本元件測試​

// components/Uploader.tsx
import { useDropup } from '@samithahansaka/dropup';

export function Uploader() {
  const { files, getDropProps, getInputProps } = useDropup({
    accept: 'image/*',
  });

  return (
    <div {...getDropProps()} data-testid="dropzone">
      <input {...getInputProps()} data-testid="file-input" />
      <p>將圖片拖放到此處</p>

      <ul data-testid="file-list">
        {files.map(file => (
          <li key={file.id} data-testid="file-item">
            {file.name}
          </li>
        ))}
      </ul>
    </div>
  );
}
// components/Uploader.test.tsx
import { render, screen } from '@testing-library/react';
import userEvent from '@testing-library/user-event';
import { describe, it, expect } from 'vitest';
import { Uploader } from './Uploader';

describe('Uploader', () => {
  it('渲染拖放區域', () => {
    render(<Uploader />);
    expect(screen.getByTestId('dropzone')).toBeInTheDocument();
    expect(screen.getByText('將圖片拖放到此處')).toBeInTheDocument();
  });

  it('接受檔案輸入', async () => {
    const user = userEvent.setup();
    render(<Uploader />);

    const input = screen.getByTestId('file-input');
    const file = new File(['test'], 'test.png', { type: 'image/png' });

    await user.upload(input, file);

    expect(screen.getByTestId('file-item')).toHaveTextContent('test.png');
  });

  it('接受多個檔案', async () => {
    const user = userEvent.setup();
    render(<Uploader />);

    const input = screen.getByTestId('file-input');
    const files = [
      new File(['test1'], 'photo1.png', { type: 'image/png' }),
      new File(['test2'], 'photo2.png', { type: 'image/png' }),
    ];

    await user.upload(input, files);

    const items = screen.getAllByTestId('file-item');
    expect(items).toHaveLength(2);
  });
});

測試拖放​

import { render, screen, fireEvent } from '@testing-library/react';
import { describe, it, expect } from 'vitest';
import { Uploader } from './Uploader';

describe('拖放', () => {
  it('拖曳時顯示拖曳狀態', () => {
    render(<Uploader />);

    const dropzone = screen.getByTestId('dropzone');

    fireEvent.dragEnter(dropzone, {
      dataTransfer: {
        types: ['Files'],
        items: [{ kind: 'file' }],
      },
    });

    expect(dropzone).toHaveAttribute('data-dragging', 'true');
  });

  it('處理檔案拖放', () => {
    render(<Uploader />);

    const dropzone = screen.getByTestId('dropzone');
    const file = new File(['test'], 'dropped.png', { type: 'image/png' });

    fireEvent.drop(dropzone, {
      dataTransfer: {
        files: [file],
        types: ['Files'],
      },
    });

    expect(screen.getByText('dropped.png')).toBeInTheDocument();
  });
});

測試驗證​

// components/ValidatedUploader.tsx
import { useDropup } from '@samithahansaka/dropup';
import { useState } from 'react';

export function ValidatedUploader() {
  const [errors, setErrors] = useState<string[]>([]);

  const { files, getDropProps, getInputProps } = useDropup({
    accept: 'image/*',
    maxSize: 1024 * 1024, // 1MB

    onValidationError: (validationErrors) => {
      const messages = validationErrors.flatMap(e => e.errors);
      setErrors(messages);
    },
  });

  return (
    <div {...getDropProps()} data-testid="dropzone">
      <input {...getInputProps()} data-testid="file-input" />

      {errors.length > 0 && (
        <ul data-testid="error-list">
          {errors.map((error, i) => (
            <li key={i} data-testid="error-item">{error}</li>
          ))}
        </ul>
      )}
    </div>
  );
}
// components/ValidatedUploader.test.tsx
import { render, screen } from '@testing-library/react';
import userEvent from '@testing-library/user-event';
import { describe, it, expect } from 'vitest';
import { ValidatedUploader } from './ValidatedUploader';

describe('驗證', () => {
  it('拒絕錯誤的檔案類型', async () => {
    const user = userEvent.setup();
    render(<ValidatedUploader />);

    const input = screen.getByTestId('file-input');
    const file = new File(['test'], 'document.pdf', { type: 'application/pdf' });

    await user.upload(input, file);

    expect(screen.getByTestId('error-list')).toBeInTheDocument();
  });

  it('拒絕超過大小限制的檔案', async () => {
    const user = userEvent.setup();
    render(<ValidatedUploader />);

    const input = screen.getByTestId('file-input');
    // 建立一個 2MB 的檔案（超過 1MB 限制）
    const content = new Array(2 * 1024 * 1024).fill('a').join('');
    const file = new File([content], 'large.png', { type: 'image/png' });

    await user.upload(input, file);

    expect(screen.getByTestId('error-list')).toBeInTheDocument();
  });
});

測試上傳​

// components/UploadingComponent.tsx
import { useDropup } from '@samithahansaka/dropup';

export function UploadingComponent() {
  const { files, actions, state, getDropProps, getInputProps } = useDropup({
    upload: { url: '/api/upload' },
  });

  return (
    <div {...getDropProps()} data-testid="dropzone">
      <input {...getInputProps()} data-testid="file-input" />

      {files.map(file => (
        <div key={file.id} data-testid="file-status">
          {file.status === 'uploading' && `上傳中: ${file.progress}%`}
          {file.status === 'complete' && '完成！'}
          {file.status === 'error' && `錯誤: ${file.error?.message}`}
        </div>
      ))}

      <button
        onClick={() => actions.upload()}
        disabled={state.isUploading}
        data-testid="upload-btn"
      >
        上傳
      </button>
    </div>
  );
}
// components/UploadingComponent.test.tsx
import { render, screen, waitFor } from '@testing-library/react';
import userEvent from '@testing-library/user-event';
import { describe, it, expect, vi, beforeEach } from 'vitest';
import { UploadingComponent } from './UploadingComponent';

// 模擬 fetch
const mockFetch = vi.fn();
global.fetch = mockFetch;

describe('上傳', () => {
  beforeEach(() => {
    mockFetch.mockReset();
  });

  it('成功上傳檔案', async () => {
    mockFetch.mockResolvedValue({
      ok: true,
      json: () => Promise.resolve({ url: 'https://example.com/file.png' }),
    });

    const user = userEvent.setup();
    render(<UploadingComponent />);

    // 新增檔案
    const input = screen.getByTestId('file-input');
    const file = new File(['test'], 'test.png', { type: 'image/png' });
    await user.upload(input, file);

    // 點擊上傳
    await user.click(screen.getByTestId('upload-btn'));

    // 等待完成
    await waitFor(() => {
      expect(screen.getByTestId('file-status')).toHaveTextContent('完成！');
    });

    expect(mockFetch).toHaveBeenCalledWith('/api/upload', expect.anything());
  });

  it('處理上傳錯誤', async () => {
    mockFetch.mockRejectedValue(new Error('網路錯誤'));

    const user = userEvent.setup();
    render(<UploadingComponent />);

    const input = screen.getByTestId('file-input');
    await user.upload(input, new File(['test'], 'test.png', { type: 'image/png' }));

    await user.click(screen.getByTestId('upload-btn'));

    await waitFor(() => {
      expect(screen.getByTestId('file-status')).toHaveTextContent('錯誤');
    });
  });
});

模擬 useDropup​

用於獨立的單元測試：

// __mocks__/@samithahansaka/dropup.ts
import { vi } from 'vitest';

export const useDropup = vi.fn(() => ({
  files: [],
  state: {
    isDragging: false,
    isDragAccept: false,
    isDragReject: false,
    isUploading: false,
    progress: 0,
    status: 'idle',
  },
  actions: {
    upload: vi.fn(),
    cancel: vi.fn(),
    remove: vi.fn(),
    reset: vi.fn(),
    retry: vi.fn(),
    addFiles: vi.fn(),
    updateFileMeta: vi.fn(),
  },
  getDropProps: vi.fn(() => ({})),
  getInputProps: vi.fn(() => ({ type: 'file' })),
  openFileDialog: vi.fn(),
}));
// 在測試中使用
import { vi } from 'vitest';
import { useDropup } from '@samithahansaka/dropup';

vi.mock('@samithahansaka/dropup');

const mockUseDropup = vi.mocked(useDropup);

describe('使用模擬的 hook', () => {
  it('渲染帶檔案的元件', () => {
    mockUseDropup.mockReturnValue({
      files: [
        { id: '1', name: 'test.png', status: 'idle', progress: 0, size: 1000, type: 'image/png' },
      ],
      // ... 其他值
    });

    render(<Uploader />);
    expect(screen.getByText('test.png')).toBeInTheDocument();
  });
});

使用 MSW 測試​

使用 Mock Service Worker 進行真實的 API 測試：

// src/test/handlers.ts
import { http, HttpResponse } from 'msw';

export const handlers = [
  http.post('/api/upload', async ({ request }) => {
    const formData = await request.formData();
    const file = formData.get('file') as File;

    return HttpResponse.json({
      url: `https://example.com/uploads/${file.name}`,
    });
  }),

  http.post('/api/upload-error', () => {
    return HttpResponse.json(
      { error: '上傳失敗' },
      { status: 500 }
    );
  }),
];
// src/test/setup.ts
import { setupServer } from 'msw/node';
import { handlers } from './handlers';

export const server = setupServer(...handlers);

beforeAll(() => server.listen());
afterEach(() => server.resetHandlers());
afterAll(() => server.close());

使用 Playwright 的端對端測試​

// e2e/upload.spec.ts
import { test, expect } from '@playwright/test';

test.describe('檔案上傳', () => {
  test('上傳檔案', async ({ page }) => {
    await page.goto('/upload');

    // 取得檔案輸入
    const fileInput = page.locator('input[type="file"]');

    // 上傳檔案
    await fileInput.setInputFiles({
      name: 'test.png',
      mimeType: 'image/png',
      buffer: Buffer.from('fake image content'),
    });

    // 驗證檔案出現在列表中
    await expect(page.locator('text=test.png')).toBeVisible();

    // 點擊上傳按鈕
    await page.click('button:has-text("上傳")');

    // 等待成功
    await expect(page.locator('text=完成')).toBeVisible();
  });

  test('拖放上傳', async ({ page }) => {
    await page.goto('/upload');

    const dropzone = page.locator('[data-testid="dropzone"]');

    // 建立檔案資料
    const buffer = Buffer.from('test content');

    // 模擬拖放
    const dataTransfer = await page.evaluateHandle(() => new DataTransfer());

    await page.dispatchEvent('[data-testid="dropzone"]', 'drop', {
      dataTransfer,
    });

    // 驗證檔案已新增
    await expect(page.locator('[data-testid="file-item"]')).toBeVisible();
  });
});

最佳實踐​

  1. 測試行為，而非實作 - 專注於使用者看到和做的事情
  2. 使用 data-testid 確保可靠性 - 避免通過 CSS 類別進行測試
  3. 模擬網路請求 - 使用 MSW 或 vi.mock 處理 API 呼叫
  4. 測試邊界情況 - 空狀態、錯誤、大檔案
  5. 測試無障礙功能 - 鍵盤導航、螢幕閱讀器