testing-library（测试库）

React Testing Library

Status: Production Ready Last Updated: 2026-02-06 Version: 16.x User Event: 14.x

Quick Start

# Install with Vitest
pnpm add -D @testing-library/react @testing-library/user-event @testing-library/jest-dom jsdom

# Or with Jest
pnpm add -D @testing-library/react @testing-library/user-event @testing-library/jest-dom

Setup File (src/test/setup.ts)

import '@testing-library/jest-dom/vitest';
import { cleanup } from '@testing-library/react';
import { afterEach } from 'vitest';

// Cleanup after each test
afterEach(() => {
  cleanup();
});

Vitest Config

// vitest.config.ts
export default defineConfig({
  test: {
    globals: true,
    environment: 'jsdom',
    setupFiles: ['./src/test/setup.ts'],
  },
});

Query Priority (Accessibility First)

Use queries in this order for accessible, resilient tests:

Examples

import { render, screen } from '@testing-library/react';

// ✅ GOOD - semantic role queries
screen.getByRole('button', { name: /submit/i });
screen.getByRole('heading', { level: 1 });
screen.getByRole('textbox', { name: /email/i });
screen.getByRole('link', { name: /learn more/i });

// ✅ GOOD - label-based queries for forms
screen.getByLabelText(/email address/i);

// ⚠️ OK - when no better option
screen.getByText(/welcome to our app/i);

// ❌ AVOID - not accessible, brittle
screen.getByTestId('submit-button');

Query Variants

When to Use Each

// Element exists immediately
const button = screen.getByRole('button');

// Check element doesn't exist
expect(screen.queryByRole('dialog')).not.toBeInTheDocument();

// Wait for async element to appear
const modal = await screen.findByRole('dialog');

// Multiple elements
const items = screen.getAllByRole('listitem');

User Event (Realistic Interactions)

Always use userEvent over fireEvent - it simulates real user behavior.

import { render, screen } from '@testing-library/react';
import userEvent from '@testing-library/user-event';

describe('Form', () => {
  it('submits form data', async () => {
    const user = userEvent.setup();
    const onSubmit = vi.fn();

    render(<LoginForm onSubmit={onSubmit} />);

    // Type in inputs
    await user.type(screen.getByLabelText(/email/i), 'test@example.com');
    await user.type(screen.getByLabelText(/password/i), 'secret123');

    // Click submit
    await user.click(screen.getByRole('button', { name: /sign in/i }));

    expect(onSubmit).toHaveBeenCalledWith({
      email: 'test@example.com',
      password: 'secret123',
    });
  });
});

Common User Events

const user = userEvent.setup();

// Clicking
await user.click(element);
await user.dblClick(element);
await user.tripleClick(element); // Select all text

// Typing
await user.type(input, 'hello world');
await user.clear(input);
await user.type(input, '{Enter}'); // Special keys

// Keyboard
await user.keyboard('{Shift>}A{/Shift}'); // Shift+A
await user.tab(); // Tab navigation

// Selection
await user.selectOptions(select, ['option1', 'option2']);

// Hover
await user.hover(element);
await user.unhover(element);

// Clipboard
await user.copy();
await user.paste();

Async Testing

findBy - Wait for Element

it('shows loading then content', async () => {
  render(<AsyncComponent />);

  // Shows loading initially
  expect(screen.getByText(/loading/i)).toBeInTheDocument();

  // Wait for content to appear (auto-retries)
  const content = await screen.findByText(/data loaded/i);
  expect(content).toBeInTheDocument();
});

waitFor - Wait for Condition

import { waitFor } from '@testing-library/react';

it('updates count after click', async () => {
  const user = userEvent.setup();
  render(<Counter />);

  await user.click(screen.getByRole('button', { name: /increment/i }));

  // Wait for state update
  await waitFor(() => {
    expect(screen.getByText(/count: 1/i)).toBeInTheDocument();
  });
});

waitForElementToBeRemoved

import { waitForElementToBeRemoved } from '@testing-library/react';

it('hides modal after close', async () => {
  const user = userEvent.setup();
  render(<ModalComponent />);

  await user.click(screen.getByRole('button', { name: /close/i }));

  // Wait for modal to disappear
  await waitForElementToBeRemoved(() => screen.queryByRole('dialog'));
});

MSW Integration (API Mocking)

Mock API calls at the network level with Mock Service Worker.

pnpm add -D msw

Setup (src/test/mocks/handlers.ts)

import { http, HttpResponse } from 'msw';

export const handlers = [
  http.get('/api/user', () => {
    return HttpResponse.json({
      id: 1,
      name: 'Test User',
      email: 'test@example.com',
    });
  }),

  http.post('/api/login', async ({ request }) => {
    const body = await request.json();
    if (body.password === 'correct') {
      return HttpResponse.json({ token: 'abc123' });
    }
    return HttpResponse.json(
      { error: 'Invalid credentials' },
      { status: 401 }
    );
  }),
];

Setup (src/test/mocks/server.ts)

import { setupServer } from 'msw/node';
import { handlers } from './handlers';

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

Test Setup

// src/test/setup.ts
import { server } from './mocks/server';
import { beforeAll, afterEach, afterAll } from 'vitest';

beforeAll(() => server.listen({ onUnhandledRequest: 'error' }));
afterEach(() => server.resetHandlers());
afterAll(() => server.close());

Using in Tests

import { server } from '../test/mocks/server';
import { http, HttpResponse } from 'msw';

it('handles API error', async () => {
  // Override handler for this test
  server.use(
    http.get('/api/user', () => {
      return HttpResponse.json(
        { error: 'Server error' },
        { status: 500 }
      );
    })
  );

  render(<UserProfile />);

  await screen.findByText(/error loading user/i);
});

Accessibility Testing

Check for A11y Violations

pnpm add -D @axe-core/react

import { axe, toHaveNoViolations } from 'jest-axe';

expect.extend(toHaveNoViolations);

it('has no accessibility violations', async () => {
  const { container } = render(<MyComponent />);
  const results = await axe(container);
  expect(results).toHaveNoViolations();
});

Role-Based Queries Are A11y Tests

Using getByRole implicitly tests accessibility:

// This passes only if button is properly accessible
screen.getByRole('button', { name: /submit/i });

// Fails if:
// - Element isn't a button or role="button"
// - Accessible name doesn't match
// - Element is hidden from accessibility tree

Testing Patterns

Forms

it('validates required fields', async () => {
  const user = userEvent.setup();
  render(<ContactForm />);

  // Submit without filling required fields
  await user.click(screen.getByRole('button', { name: /submit/i }));

  // Check for validation errors
  expect(screen.getByText(/email is required/i)).toBeInTheDocument();
  expect(screen.getByText(/message is required/i)).toBeInTheDocument();
});

Modals/Dialogs

it('opens and closes modal', async () => {
  const user = userEvent.setup();
  render(<ModalTrigger />);

  // Modal not visible initially
  expect(screen.queryByRole('dialog')).not.toBeInTheDocument();

  // Open modal
  await user.click(screen.getByRole('button', { name: /open/i }));
  expect(screen.getByRole('dialog')).toBeInTheDocument();

  // Close modal
  await user.click(screen.getByRole('button', { name: /close/i }));
  await waitForElementToBeRemoved(() => screen.queryByRole('dialog'));
});

Lists

it('renders list items', () => {
  render(<TodoList items={['Buy milk', 'Walk dog']} />);

  const items = screen.getAllByRole('listitem');
  expect(items).toHaveLength(2);
  expect(items[0]).toHaveTextContent('Buy milk');
});

Common Matchers (jest-dom)

// Presence
expect(element).toBeInTheDocument();
expect(element).toBeVisible();
expect(element).toBeEmptyDOMElement();

// State
expect(button).toBeEnabled();
expect(button).toBeDisabled();
expect(checkbox).toBeChecked();
expect(input).toBeRequired();

// Content
expect(element).toHaveTextContent(/hello/i);
expect(element).toHaveValue('test');
expect(element).toHaveAttribute('href', '/about');

// Styles
expect(element).toHaveClass('active');
expect(element).toHaveStyle({ color: 'red' });

// Focus
expect(input).toHaveFocus();

Debugging

screen.debug()

it('debugs rendering', () => {
  render(<MyComponent />);

  // Print entire DOM
  screen.debug();

  // Print specific element
  screen.debug(screen.getByRole('button'));
});

logRoles

import { logRoles } from '@testing-library/react';

it('shows available roles', () => {
  const { container } = render(<MyComponent />);
  logRoles(container);
});

Common Mistakes

Using getBy for Async

// ❌ WRONG - fails if element appears async
const modal = screen.getByRole('dialog');

// ✅ CORRECT - waits for element
const modal = await screen.findByRole('dialog');

Not Awaiting User Events

// ❌ WRONG - race condition
user.click(button);
expect(result).toBeInTheDocument();

// ✅ CORRECT - await the interaction
await user.click(button);
expect(result).toBeInTheDocument();

Using container.querySelector

// ❌ WRONG - not accessible, brittle
const button = container.querySelector('.submit-btn');

// ✅ CORRECT - accessible query
const button = screen.getByRole('button', { name: /submit/i });

See Also

• vitest skill - Test runner configuration
• testing-patterns skill - General testing patterns
• Official docs: https://testing-library.com/docs/react-testing-library/intro