用酶进行反应测试，componentDidMount更新HTML()

import React from 'react';
import { shallow } from 'enzyme';

class MyComponent extends React.Component {
  componentDidMount() {
    this.updateHTML();
  }

  updateHTML() {
    // 更新HTML的逻辑
  }

  render() {
    return <div>Hello World</div>;
  }
}

describe('MyComponent', () => {
  it('should call updateHTML method on componentDidMount', () => {
    const wrapper = shallow(<MyComponent />);
    const instance = wrapper.instance();
    jest.spyOn(instance, 'updateHTML');
    instance.componentDidMount();
    expect(instance.updateHTML).toHaveBeenCalled();
  });
});