TypeError：environment.teardown不是在应用解决方案后开玩笑的函数错误

Question

我正在使用Linux Mint OS。我正在react.js中学习 public class BasicHttpServerExample2 { public static void main(String[] args) throws IOException { int port = 88; InetSocketAddress socket = new InetSocketAddress("192.168.0.37", port); HttpServer server = HttpServer.create(); server.bind(socket, port); System.out.println("server started at " + port); HttpContext rootContext = server.createContext("/"); HttpContext context = server.createContext("/print"); rootContext.setHandler(BasicHttpServerExample2::RootHandler); context.setHandler(BasicHttpServerExample2::handleRequest); server.start(); } public static void RootHandler(HttpExchange he) throws IOException { String response = "<h1>Server start success if you see this message</h1>" + "<h1>Port: " + "88" + "</h1>"; he.sendResponseHeaders(200, response.length()); OutputStream os = he.getResponseBody(); os.write(response.getBytes()); os.close(); } private static void handleRequest(HttpExchange exchange) throws IOException { /** handler resoponse **/ URI requestURI = exchange.getRequestURI(); printRequestInfo(exchange); /** handler resoponse **/ String response = "Data Received"; exchange.getResponseHeaders().add("Access-Control-Allow-Origin", "*"); /** handler resoponse **/ exchange.sendResponseHeaders(200, response.getBytes().length); /** handler resoponse **/ OutputStream os = exchange.getResponseBody(); /** handler resoponse **/ os.write(response.getBytes()); /** handler resoponse **/ os.close(); } private static void printRequestInfo(HttpExchange exchange) { /** Console ***/ System.out.println("-- headers --"); Headers requestHeaders = exchange.getRequestHeaders(); requestHeaders.entrySet().forEach(System.out::println); /** Console ***/ System.out.println("-- principle --"); HttpPrincipal principal = exchange.getPrincipal(); System.out.println(principal); /** Console ***/ System.out.println("-- HTTP method --"); String requestMethod = exchange.getRequestMethod(); System.out.println(requestMethod); /** Console ***/ System.out.println("-- query --"); URI requestURI = exchange.getRequestURI(); String query = requestURI.getQuery(); SimpleDateFormat formatter= new SimpleDateFormat("yyyy-MM-dd 'at' HH:mm:ss z"); Date date = new Date(System.currentTimeMillis()); System.out.println(query + " received at " + formatter.format(date)); } } 。我使用Testing创建了一个应用。我使用create react app安装了jest-cli。我的文件夹结构如下

我的测试如下所示

App.test.js

sudo npm i -g jest-cli

我的package.json如下所示

package.json

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);
  ReactDOM.unmountComponentAtNode(div);
});


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

我遇到错误

我读了this SO post。按照该帖子的说明，我按照以下步骤操作

1. 删除package-lock.json和node_modules。
2. 从package.json中的依赖项中删除笑话（在我的设置中不存在）
3. 然后执行npm安装。

但是我仍然遇到错误。

Answer 1

您不需要安装jest-cli，这可能是导致错误的原因。 create react app已经开玩笑了，请尝试从全局依赖项中删除jest-cli并运行npm test。

Answer 2

删除所有的node_modules（删除node modules文件夹）。然后使用myhost/second或yarn安装它们，使用npm install或npm test命令运行测试。