javascript - 使用 Jest 测试组件
问题描述
一般来说,我是 Jest 和 JavaScript 的新手。我正在尝试用 Jest 测试我的 java 脚本代码。
安装 Jest 和所有其他依赖项后,初始 App.test.js 将失败并显示以下消息:
FAIL src/App.test.js
● Test suite failed to run
TypeError: Cannot read property 'bool' of undefined
2 | import logo from './logo.svg';
3 | import './App.css';
> 4 | import { Grid, Row, Col, Table, Panel, Image, Tabs, Tab, Nav, NavItem, Alert} from 'react-bootstrap';
| ^
5 | import _ from 'lodash';
6 | import $ from 'jquery';
7 | import Request from 'react-http-request';
at Object.<anonymous> (node_modules/react-overlays/lib/Transition.js:259:33)
at Object.<anonymous> (node_modules/react-bootstrap/lib/Collapse.js:41:19)
at Object.<anonymous> (node_modules/react-bootstrap/lib/index.js:62:18)
at Object.<anonymous> (src/App.js:4:1)
at Object.<anonymous> (src/App.test.js:3:1)
我的问题是我怎样才能使这个测试通过?
当这是我的 package.json 时,我知道这个测试应该成功通过:
{
"name": "my-app",
"version": "0.1.0",
"private": true,
"devDependencies": {
"babel-jest": "^23.4.2",
"babel-polyfill": "^6.26.0",
"babel-preset-es2015": "^6.24.1",
"babel-preset-react": "^6.24.1",
"enzyme": "^3.5.1",
"jest": "^23.5.0",
"react-addons-test-utils": "^15.6.2",
"react-dom": "^16.4.2",
"react-scripts": "0.6.1",
"react-test-renderer": "^16.4.2"
},
"dependencies": {
"adal-angular": "^1.0.13",
"axios": "^0.15.3",
"bootstrap": "^3.3.7",
"jquery": "^3.1.1",
"lodash": "^4.17.10",
"react": "^16.4.2",
"react-bootstrap": "^0.30.5",
"react-bootstrap-typeahead": "^1.2.0",
"react-http-request": "^1.0.2"
},
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "jest",
"eject": "react-scripts eject"
},
"description": "This project was bootstrapped with [Create React App (https://github.com/facebookincubator/create-react-app).",
"main": "index.js",
"author": "",
"license": "ISC",
"jest": {
"moduleNameMapper": {
"\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/__mocks__/fileMock.js",
"\\.(css|less)$": "<rootDir>/__mocks__/styleMock.js"
},
"resolver": null
}
.babelrc
{
"presets": ["env", "react"]
}
应用程序.js
import React, { Component } from 'react';
import logo from './logo.svg';
import './App.css';
import { Grid, Row, Col, Table, Panel, Image, Tabs, Tab, Nav, NavItem, Alert} from 'react-bootstrap';
import _ from 'lodash';
import $ from 'jquery';
import Request from 'react-http-request';
import {AdminViewComponent} from './components/AdminViewComponent.js';
import {WholeScreen} from './components/WholeScreenComponent.js';
class App extends Component {
render() {
var url = "./api/user/" + this.props.userName + "/";
console.log("props = " + JSON.stringify(this.props));
console.log("url = " + url);
var userCompanyIcon;
//if (this.props.tid == "49d3d3cf-cde6-4161-8d6d-1789042d7b01"){
if (this.props.tid == "72f988bf-86f1-41af-91ab-2d7cd011db47" || this.props.tid == "49d3d3cf-cde6-4161-8d6d-1789042d7b01"){
userCompanyIcon = <Image className="userCompanyIcon" src="microsoftgray.png" responsive/>;
}
return (
<div className="App">
<div className="App-header">
<Grid>
<Row>
<Col xs={6} sm={6} md={6}>
</Col>
<Col xs={2} sm={2} md={2}>
</Col>
<Col xs={4} sm={4} md={4}>
<div className="Hello">Hello, {this.props.fisrtName} </div>
</Col>
</Row>
<Row>
<Col xs={4} sm={4} md={4} >
{userCompanyIcon}
</Col>
<Col xs={4} sm={4} md={4} >
</Col>
<Col xs={4} sm={4} md={4}>
<Image className="companyIcon" src="MatanTransperent.png" responsive />
</Col>
</Row>
</Grid>
</div>
<div className="App-content">
<Request
url= {url}
method='get'
accept='application/json'
headers={{'Authorization': 'Bearer ' + this.props.token}}
verbose={true}>
{
({error, result, loading}) => {
if (loading) {
return <div>loading...</div>;
} else {
if (result == null || result.statusType == 4 ||result.statusType == 5){
return <div> an unknown error has occured. </div>;
}
else{
var returnObject = JSON.parse(result.text);
if (returnObject.isAdmin == false){
return <WholeScreen data {returnObject.DonationsList}/>;
}
else if (returnObject.isAdmin == true){
return <AdminViewComponent token={this.props.token}/>;
}
}
}
}
}
</Request>-
</div>
</div>
);
}
}
export default App;
解决方案
您面临的问题是:您使用webpack能够导入静态文件,在您的情况下,是 SVG 图像。Jest 不通过 webpack 运行 JavaScript 源代码和测试文件,只通过 Babel,它只支持导入 JavaScript 模块。
Jest 文档中解释了如何处理此问题的解决方案:https ://jestjs.io/docs/en/webpack#handling-static-assets
你必须告诉 test:“好的,如果你遇到我正在导出 SVG 或其他静态文件的行,只需导入一个模拟 JavaScript 模块。”</p>
这是通过将其添加到 package.json 中的 Jest 配置来完成的:
// package.json
{
"jest": {
"moduleNameMapper": {
"\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/__mocks__/fileMock.js"
}
}
}
…然后你__mocks__
在项目的根目录中创建一个目录并将这个文件fileMock.js
放在那里:
// __mocks__/fileMock.js
module.exports = 'test-file-stub';
您可能会遇到的下一个问题是导入 CSS 文件,您应该稍微不同地处理这些文件,使用styleMock
:
// package.json
{
"jest": {
"moduleNameMapper": {
"\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$": "<rootDir>/__mocks__/fileMock.js",
"\\.(css|less)$": "<rootDir>/__mocks__/styleMock.js"
}
}
}
模拟文件:
// __mocks__/styleMock.js
module.exports = {};
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到 json 然后在@interceptor 中打印它