测试React：目标容器不是DOM元素

小编典典

测试React：目标容器不是DOM元素

reactjs

我正在尝试在使用Webpack时使用Jest / Enzyme测试React组件。

我有一个非常简单的测试@

import React from 'react';
import { shallow } from 'enzyme';

import App from './App';

it('App', () => {
  const app = shallow(<App />);
  expect(1).toEqual(1);
});

它要拾取的相对组件是：

import React, { Component } from 'react';
import { render } from 'react-dom';

// import './styles/normalize.css';

class App extends Component {
  render() {
    return (
      <div>app</div>
    );
  }
}

render(<App />, document.getElementById('app'));

但是，运行jest会导致失败：

Invariant Violation: _registerComponent(...): Target container is not a DOM element.

有错误@

at Object.<anonymous> (src/App.js:14:48) at Object.<anonymous> (src/App.test.js:4:38)

测试文件引用第4行，该行是的导入<App />，导致失败。堆栈跟踪显示第14行App.js是失败的原因-仅仅是来自的render调用react- dom，这是我从未遇到过的挑战（该应用程序可从我的Webpack设置正确渲染）。

对于那些感兴趣的人（Webpack代码）：

module.exports = {
  entry: './src/App',
  output: {
    filename: 'bundle.js',
    path: './dist'
  },
  module: {
    loaders: [
      {
        test: /\.js?$/,
        exclude: /node_modules/,
        loader: 'babel',
        query: {
          presets: ['react', 'es2015']
        }
      },
      {
        test: /\.css$/,
        loader: 'style!css-loader?modules&importLoaders=1&localIdentName=[name]__[local]___[hash:base64:5]'
      },
      {
        test: /\.scss$/,
        loader: 'style!css-loader?modules&importLoaders=1&localIdentName=[name]__[local]___[hash:base64:5]!sass'
      }
    ]
  }
}

而我的package.json：

{
  "name": "tic-tac-dux",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "dev": "webpack-dev-server --devtool eval --progress --colors --inline --hot --content-base dist/",
    "test": "jest"
  },
  "jest": {
    "moduleNameMapper": {
      "^.+\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/__mocks__/fileMock.js",
      "^.+\\.(css|sass)$": "<rootDir>/__mocks__/styleMock.js"
    }
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "babel-core": "^6.17.0",
    "babel-jest": "^16.0.0",
    "babel-loader": "^6.2.5",
    "babel-polyfill": "^6.16.0",
    "babel-preset-es2015": "^6.16.0",
    "babel-preset-react": "^6.16.0",
    "css-loader": "^0.25.0",
    "enzyme": "^2.4.1",
    "jest": "^16.0.1",
    "jest-cli": "^16.0.1",
    "node-sass": "^3.10.1",
    "react-addons-test-utils": "^15.3.2",
    "react-dom": "^15.3.2",
    "sass-loader": "^4.0.2",
    "style-loader": "^0.13.1",
    "webpack": "^1.13.2",
    "webpack-dev-server": "^1.16.2"
  },
  "dependencies": {
    "react": "^15.3.2",
    "react-dom": "^15.3.2"
  }
}

哦，如果有人要说在脚本之前没有加载div元素，这是我的index.html：

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>App</title>
  </head>
  <body>
    <div id="app"></div>
    <script src="/bundle.js"></script>
  </body>
</html>

这个特殊的渲染问题可能是什么原因？与新的Jest更新到15.0有关吗？

阅读 404

2020-07-22

共1个答案

小编典典

App.jsx应该导出App类并且不执行其他操作，render应在其他位置调用。

如果render从App.jsx中删除该调用，该错误应消失，因为测试环境未提供具有appID 的DOM，所以该错误会弹出。

2020-07-22