当Component.prototype返回undefined时，如何使用jest/酶对componentDidMount进行单元测试？

npm install jest enzyme enzyme-adapter-react-16 react-test-renderer --save-dev

import { configure } from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';

configure({ adapter: new Adapter() });

import React from 'react';
import { shallow } from 'enzyme';
import MyComponent from './MyComponent';

describe('MyComponent', () => {
  let wrapper;

  beforeEach(() => {
    wrapper = shallow(<MyComponent />);
  });

  afterEach(() => {
    jest.clearAllMocks();
  });

  it('should call componentDidMount', () => {
    const componentDidMountSpy = jest.spyOn(MyComponent.prototype, 'componentDidMount');
    wrapper.instance().componentDidMount();
    expect(componentDidMountSpy).toHaveBeenCalled();
  });

  // 其他的测试用例...
});