Jest酶测试引发意外的令牌错误

Question

当我运行测试时，代码中出现了“意外的令牌错误：

const wrapper = shallow(<WelcomeMessage/>");

错误被抛出到“(

我写过笑话测试。这是我第一次使用酶和react编写测试用例。所以我不熟悉这个设置。我已经安装了：babel jest、react dom、babel插件转换导出扩展、enzyme-adapter-react-16、react测试渲染器、@babel/preset env和@babel/core

package.json：

{
  "private": true,
  "version": "0.0.0",
  "name": "example-jquery",
  "devDependencies": {
    "@babel/core": "*",
    "@babel/preset-env": "^7.4.4",
    "babel-jest": "^24.8.0",
    "babel-plugin-transform-export-extensions": "^6.22.0",
    "enzyme": "^3.9.0",
    "enzyme-adapter-react-16": "^1.12.1",
    "jest": "^24.8.0",
    "jest-dom": "^3.1.4",
    "jest-useragent-mock": "0.0.3"
  },
  "dependencies": {
    "jest-puppeteer": "^4.1.1",
    "jquery": "^3.4.1",
    "jsdom": "^15.0.0",
    "puppeteer": "^1.15.0",
    "react": "^16.8.6",
    "react-dom": "^16.8.6",
    "react-test-renderer": "^16.8.6"
  },
  "scripts": {
    "test": "jest --verbose"
  },
  "jest": {
    "transform": {
      "^.+\\.jsx?$": "babel-jest"
    }
  }
}

jest.config.js：

module.exports = {
  preset: 'jest-puppeteer',
  "bail": 0,
  setupFiles: ['<rootDir>/enzyme.config.js'],
  moduleFileExtensions: ['js', 'json', 'jsx'],
  transformIgnorePatterns: ['<rootDir>/node_modules/']
}

enzyme.config.js：

const Enzyme = require('enzyme');
const Adapter = require('enzyme-adapter-react-16');

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

. Babelrc：

{
  "presets": ["@babel/preset-env"],
  "plugins": ["transform-export-extensions"],
  "only": [
        "./**/*.js",
        "node_modules/jest-runtime"
      ]
}

欢迎essage.test.js：

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

// Components
import WelcomeMessage from './WelcomeMessage';

function setup() {
  const props = {
    imgPath: 'some/image/path/to/a/mock/image',
  };
  const wrapper = shallow(<WelcomeMessage />);
  return { wrapper, props };
}

describe('WelcomeMessage Test Suite', () => {
  it('Should have an image', () => {
    const { wrapper } = setup();
    expect(wrapper.find('img').exists()).toBe(true);
  });
});

Answer 1

这一行：

<WelcomeMessage />

是JSX，它“只为React.createElement函数提供语法糖”。

由于JSX实际上不是有效的JavaScript代码，因此必须将其编译为React.createElement调用。

这是由Babel插件@Babel/plugin transform react jsx完成的，它是@Babel/preset react的一部分。

添加@Babel/preet-reacts到您的Babel配置，这应该可以解决问题。