reactjs App.test.js出错

Question

尝试为安装reactjs时获得的App.test.js运行npm.test时出现此错误.有关如何解决这个问题的任何想法？我现在添加了一些额外的代码等.

> client@0.1.0 test /Users/filipmyllari/Documents/1DV430/fm222hp- 
project/client
react-scripts test --env=jsdom

>2018-05-29 16:26 node[535] (FSEvents.framework) FSEventStreamStart: 
register_with_server: ERROR: f2d_register_rpc() => (null) (-22)
2018-05-29 16:26 node[535] (FSEvents.framework) FSEventStreamStart: 
register_with_server: ERROR: f2d_register_rpc() => (null) (-22)
events.js:182
  throw er; // Unhandled 'error' event
  ^

>Error: Error watching file for changes: EMFILE
at _errnoException (util.js:1019:11)
at FSEvent.FSWatcher._handle.onchange (fs.js:1360:9)
npm ERR! Test failed.  See above for more details.

这是package.json文件

{
 "name": "client",
 "version": "0.1.0",
 "private": true,
 "dependencies": {
 "add": "^2.0.6",
 "babel-jest": "^23.0.1",
 "babel-preset-env": "^1.7.0",
 "babel-preset-react": "^6.24.1",
 "firebase": "^4.13.1",
 "jest": "^23.0.1",
 "lodash": "^4.17.5",
 "react": "^16.3.1",
 "react-dom": "^16.3.1",
 "react-router-dom": "^4.2.2",
 "react-scripts": "1.1.4",
 "react-test-renderer": "^16.4.0",
 "yarn": "^1.7.0"
 },
 "scripts": {
 "start": "react-scripts start",
 "build": "react-scripts build",
 "test": "react-scripts test --env=jsdom",
 "eject": "react-scripts eject"
},
"devDependencies": {
 "enzyme": "^3.3.0",
 "react-addons-test-utils": "^15.6.2"
}
}

代码如下(App.test.js)

import React from 'react'
import ReactDOM from 'react-dom'
import App from './App'

it('renders without crashing', () => {
  const div = document.createElement('div')
  ReactDOM.render(<App />, div)
})

describe('Addition', () => {
  it('knows that 2 and 2 make 4', () => {
    expect(2 + 2).toBe(4);
  });
});

Answer 1

这是使用 Jest 进行测试时的常见问题。

我建议您watchman按照Jest issues 1767中的建议进行安装。

brew install watchman

安装任何测试后应该不会出现问题，它已经解决了我和我的一些同事计算机上的此类问题，因此我相信它也值得您尝试。

此外，有关该问题的一些最新回复建议更新 Jest 以忽略该错误：

最终，更新到 Jest 23.1.0 解决了该问题。 （释放）