App.test.js

import React from 'react';
import renderer from 'react-test-renderer';
import { ActivityIndicator } from 'react-native';
import TeamsList from './src/components/TeamsList';
import App from './App';

it('renders the loading component when the app is first rendered', () => {
  const rendered = renderer.create(<App />);
  const TeamsListRendered = rendered.root.findByType(TeamsList);
  const ActivityIndicatorRendered = TeamsListRendered.findByType(ActivityIndicator);
  expect(ActivityIndicatorRendered).toBeTruthy();
});