text: import React from 'react';
  import renderer from 'react-test-renderer';
  import { MemoryRouter } from 'react-router-dom';
  import App from './MainApp';
  
  it('renders without crashing', () => {
    const tree = renderer.create(<MemoryRouter><App /></MemoryRouter>).toJSON();
  
    expect(tree).not.toBe(undefined);
  });
  