jest-setup-tests.js

import React from 'react';
import Enzyme, { shallow } from 'enzyme';
import Adapter from '@wojtekmaj/enzyme-adapter-react-17';
import { createSerializer } from 'enzyme-to-json';

// Set the default serializer for Jest to be the from enzyme-to-json
// This produces an easier to read (for humans) serialized format.
expect.addSnapshotSerializer(createSerializer({ mode: 'deep' }));

// React 16 Enzyme adapter
Enzyme.configure({ adapter: new Adapter() });

// Define globals to cut down on imports in test files
global.React = React;
global.shallow = shallow;

// Use fake timers for async events
jest.useFakeTimers();