__tests__

import { sum } from './utils';

test('sum adds numbers correctly', () => {
  expect(sum(1, 2)).toBe(3);
});

npm test
# или
yarn test

PASS  __tests__/example.test.js
✓ sum adds numbers correctly (3ms)

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        0.543s

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

import { render, fireEvent } from '@testing-library/react-native';
import MyButton from './MyButton';

test('button triggers callback on press', () => {
  const onPressMock = jest.fn();
  const { getByText } = render(<MyButton onPress={onPressMock} noscript="Click me" />);

  fireEvent.press(getByText('Click me'));
  expect(onPressMock).toHaveBeenCalledTimes(1);
});

npm test

test.only('кнопка вызывает onPress', () => {
  expect(true).toBe(true);
});

npm install -g detox-cli
npm install detox --save-dev

describe('Login Flow', () => {
  beforeAll(async () => {
    await device.launchApp();
  });

  it('should log in successfully', async () => {
    await element(by.id('username')).typeText('testuser');
    await element(by.id('password')).typeText('password123');
    await element(by.id('loginButton')).tap();
    await expect(element(by.id('welcomeMessage'))).toBeVisible();
  });
});

detox test

detox test -c ios.sim.debug 
detox test -c android.emu.debug

//или запуск конкретного теста
detox test e2e/login.test.js

detox[42012] INFO:  [test.js] Running tests...
detox[42012] INFO:  Login Flow
detox[42012] INFO:    ✓ should log in successfully(1.2s)
detox[42012] INFO:  Tests successful!