Тестирование React Native: Jest + Detox

1// jest.config.js
2module.exports = {
3  preset: 'react-native',
4  setupFilesAfterSetup: ['./jest.setup.js'],
5  transformIgnorePatterns: [
6    'node_modules/(?!(react-native|@react-native|@react-navigation)/)',
7  ],
8  moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json'],
9};

1// utils/formatters.test.js
2import { formatCurrency, formatDate } from './formatters';
3
4describe('formatCurrency', () => {
5  it('formats number as currency', () => {
6    expect(formatCurrency(1234.56)).toBe('1 234,56 ₽');
7  });
8
9  it('handles zero', () => {
10    expect(formatCurrency(0)).toBe('0,00 ₽');
11  });
12});
13
14describe('formatDate', () => {
15  it('formats date in Russian locale', () => {
16    const date = new Date('2024-01-15');
17    expect(formatDate(date)).toBe('15 января 2024');
18  });
19});

1npm install --save-dev @testing-library/react-native

1import { render, fireEvent, waitFor } from '@testing-library/react-native';
2import LoginScreen from '../screens/LoginScreen';
3
4describe('LoginScreen', () => {
5  it('renders login form', () => {
6    const { getByPlaceholderText, getByText } = render(<LoginScreen />);
7
8    expect(getByPlaceholderText('Email')).toBeTruthy();
9    expect(getByPlaceholderText('Пароль')).toBeTruthy();
10    expect(getByText('Войти')).toBeTruthy();
11  });
12
13  it('shows error on invalid credentials', async () => {
14    const { getByText, getByPlaceholderText } = render(<LoginScreen />);
15
16    fireEvent.changeText(
17      getByPlaceholderText('Email'),
18      'wrong@email.com'
19    );
20    fireEvent.changeText(
21      getByPlaceholderText('Пароль'),
22      'wrongpassword'
23    );
24    fireEvent.press(getByText('Войти'));
25
26    await waitFor(() => {
27      expect(getByText('Неверные данные')).toBeTruthy();
28    });
29  });
30});

1// __mocks__/@react-native-async-storage/async-storage.js
2export default {
3  setItem: jest.fn(() => Promise.resolve()),
4  getItem: jest.fn(() => Promise.resolve(null)),
5  removeItem: jest.fn(() => Promise.resolve()),
6  clear: jest.fn(() => Promise.resolve()),
7};

1npm install --save-dev detox
2npx detox init

1{
2  "configurations": {
3    "ios.debug": {
4      "device": "ios.simulator",
5      "app": "ios.debug"
6    },
7    "android.debug": {
8      "device": "android.emulator",
9      "app": "android.debug"
10    }
11  }
12}

1describe('Login Flow', () => {
2  beforeAll(async () => {
3    await device.launchApp();
4  });
5
6  beforeEach(async () => {
7    await device.reloadReactNative();
8  });
9
10  it('should login successfully', async () => {
11    await element(by.id('email-input')).typeText('user@example.com');
12    await element(by.id('password-input')).typeText('password123');
13    await element(by.id('login-button')).tap();
14
15    await expect(element(by.id('home-screen'))).toBeVisible();
16  });
17
18  it('should show validation errors', async () => {
19    await element(by.id('login-button')).tap();
20
21    await expect(element(by.text('Email обязателен'))).toBeVisible();
22  });
23});

1import nock from 'nock';
2
3beforeEach(() => {
4  nock('https://api.example.com')
5    .get('/users/1')
6    .reply(200, { id: 1, name: 'John' });
7});
8
9afterEach(() => {
10  nock.cleanAll();
11});