使用 React Native 0.61.0 从“setupJest.js”中找不到模块“EventEmitter”

Question

setupJest.js在运行 React Native 测试之前，我使用了以下文件。

// Required to correctly polyfill React-Native

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

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

global.XMLHttpRequest = jest.fn();
global.fetch = jest.fn();

if (typeof window !== 'object') {
  global.window = global;
  global.window.navigator = {};
}

const EventEmitter = require('EventEmitter');
const RCTDeviceEventEmitter = require('RCTDeviceEventEmitter');

class NativeEventEmitter extends EventEmitter {
  constructor() {
    super(RCTDeviceEventEmitter.sharedSubscriber);
  }
}

这是一个示例测试：

/**
 * @format
 */

import 'react-native';
import React from 'react';
import App from '../App';

// Note: test renderer must be required after react-native.
import renderer from 'react-test-renderer';

jest.mock('NativeEventEmitter');

it('renders correctly', () => {
  renderer.create(<App />);
});

这适用于 React Native 0.60.x。但是，使用 React Native 0.61.0，我收到以下错误：

Cannot find module 'EventEmitter' from 'setupJest.js'

如果我更改我的导入以匹配文件所在的位置node_modules，我不会得到更多。

const EventEmitter = require('react-native/Libraries/vendor/emitter/EventEmitter');
const RCTDeviceEventEmitter = require('react-native/Libraries/EventEmitter/RCTDeviceEventEmitter');

知道如何更新我的代码以使其适用于 React Native 0.61.0 吗？

Cannot find module 'NativeEventEmitter' from 'App-test.js'

  10 | import renderer from 'react-test-renderer';
  11 | 
> 12 | jest.mock('NativeEventEmitter');
     | ^
  13 | 
  14 | it('renders correctly', () => {
  15 |   renderer.create(<App />);

  at Resolver.resolveModule (node_modules/jest-resolve/build/index.js:259:17)
  at Object.<anonymous> (tests/App-test.js:12:1)

您可以通过克隆以下 repo 并运行其测试来重现此问题：

git clone -b react-native-61 https://github.com/mraible/samples-js-react-native.git
cd samples-js-react-native/browser-sign-in
npm i
npm test

Answer 1

RN 库具有NativeEventEmitter该类的模拟实现。只需从 setupJest.js 中删除以下代码：

const EventEmitter = require('EventEmitter');
const RCTDeviceEventEmitter = require('RCTDeviceEventEmitter');

class NativeEventEmitter extends EventEmitter {
  constructor() {
    super(RCTDeviceEventEmitter.sharedSubscriber);
  }
}

并在您的测试文件中设置模拟：

jest.mock(
  '../node_modules/react-native/Libraries/EventEmitter/NativeEventEmitter',
);

不要忘记删除：

jest.mock('NativeEventEmitter');