import React from 'react'; import { render } from '@testing-library/react'; import '@testing-library/jest-dom/extend-expect'; import Error from '../pages/_error'; test('ErrorPage ', () => { const { getByText, rerender } = render(); expect(getByText('An error 500 occurred on server')).toBeInTheDocument(); // Change props rerender(); expect(getByText('An error occurred on client')).toBeInTheDocument(); });