javascript - Jest - React 组件中的模拟粗箭头功能

Question

鉴于我的组件和下面的测试，为什么我的 confirmClickHandler 方法在我运行测试时仍然被调用？

注意:我注意到，当我将方法从粗箭头函数更改为常规函数时，它会被正确地模拟出来。我在这里缺少什么？

class CalendarConfirmation extends React.Component {
  ...

  confirmClickHandler = (e) =>  {
  ...
  }
}

和我的测试:

import React from 'react';
import {mount} from 'enzyme';
import CalendarConfirmation from '../components/CalendarConfirmation';

describe('Test CalendarConfirmation', () => {
  let calendarConfirmation;
  calendarConfirmation = mount (<CalendarConfirmation />);
  calendarConfirmation.instance().confirmClickHandler = jest.fn();
  ...
}

Answer 1

这对我有用:

import React from 'react'
import { mount, shallow } from 'enzyme'

class Foo extends React.Component {
  // babel transpiles this too Foo.prototype.canMock
  protoMethod () {
    // will be mocked
  }

  // this becomes an instance property
  instanceMethod = () => {
    return 'NOT be mocked'
  }

  render () {
    return (<div>{`${this.protoMethod()} ${this.instanceMethod()}`}</div>)
  }
}

Foo.prototype.protoMethod = jest.fn().mockReturnValue('you shall')

it('should be mocked', () => {
  const mock = jest.fn().mockReturnValue('be mocked')
  const wrapper = mount(<Foo />)
  wrapper.instance().instanceMethod = mock
  wrapper.update()
  expect(mock).toHaveBeenCalled()
})

但是请注意，当使用 shallow 而不是 mount 时，这会失败。