嘲笑未嘲笑的方法的调用

Question

我有一个React组件MyComponent，我想在其中测试用户旋转手机时应触发的行为。在组件内部：export class MyComponent extends React.PureComponent<props> {  componentDidMount() {    window.addEventListener('orientationchange', this.onRotation)  }  componentWillUnmount() {    window.removeEventListener('orientationchange', this.onRotation)  }  onRotation = () => {    // do things  }  render() {    // ...  }}我在介质上找到了一篇文章，描述了如何在此处编写测试。但是，这对我不起作用。describe('<MyComponent />', () => {  it('does things on rotation', () => {    const map : any = {}    window.addEventListener = jest.fn((event, cb) => {      map[event] = cb;    })    const wrapper : any = mount(<MyComponent />)    map.orientationchange()    expect(wrapper.onRotation).toHaveBeenCalled()  })})在这篇文章中，此方法有效，但是出现错误："Matcher error: received value must be a mock or spy functionReceived has value: undefined"使用间谍也行不通：it('does things on rotation', () => {    const map : any = {}    window.addEventListener = jest.fn((event, cb) => {      map[event] = cb;    })    const wrapper : any = mount(<MyComponent />)    const spy = jest.spyOn(wrapper.instance(), 'onRotation')    map.orientationchange()    expect(spy).toHaveBeenCalled()})它说："Expected mock function to have been called, but it was not called."

Answer 1

监视onRotation内部的函数。

import React from 'react';

class OrientationChange extends React.Component {

    componentDidMount() {

      window.addEventListener('orientationchange', this.onRotation)

    }

    componentWillUnmount() {

      window.removeEventListener('orientationchange', this.onRotation)

    }

    handleRotation = () => {

      console.log('inside handle rotation');

    }

    onRotation = (event) => {

      this.handleRotation()

    }

    render() {

        return (

          <div>Testing</div>

        )

    }

}

export default OrientationChange;

describe('<OrientationChange /> orientation change test', () => {

  it('does things on rotation', () => {

    const map = {}

    window.addEventListener = jest.fn((event, cb) => {

      map[event] = cb;

    })

    const wrapper = mount(<OrientationChange />)

    const spy = jest.spyOn(wrapper.instance(), 'handleRotation')

    map.orientationchange();

    expect(spy).toHaveBeenCalled()

  })

})