shallowWrapper 为空，正在测试快照 Jest/Enzyme？

Question

我不知道为什么我在运行快照测试时得到空的 shallowWrapper 对象，我正在使用 Jest 和酶:

我在 App.test.js.snap 文件中得到的内容：

// Jest Snapshot v1, "goo.gl/fbAQLP"
exports[`renders App component 1`] = `ShallowWrapper {}`;

我的package.json文件：

{
  "name": "test",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@fortawesome/fontawesome-svg-core": "^1.2.30",
    "@fortawesome/free-solid-svg-icons": "^5.14.0",
    "@fortawesome/react-fontawesome": "^0.1.11",
    "@testing-library/jest-dom": "^4.2.4",
    "@testing-library/react": "^9.3.2",
    "@testing-library/user-event": "^7.1.2",
    "bootstrap": "^4.5.2",
    "install": "^0.13.0",
    "npm": "^6.14.8",
    "react": "^16.13.1",
    "react-bootstrap": "^1.3.0",
    "react-dom": "^16.13.1",
    "react-router-dom": "^5.2.0",
    "react-scripts": "^4.0.0-next.98"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": "react-app"
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  },
  "devDependencies": {
    "enzyme": "^3.11.0",
    "enzyme-adapter-react-16": "^1.15.4",
    "jest": "^26.4.2"
  }
}

App.test.js 文件

import { shallow } from 'enzyme';
import React from 'react';
import App from './App';


it('renders App component', () => {
  expect(shallow(<App />)).toMatchSnapshot();
})

setupTests.js 文件:

import { configure } from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';

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

为什么我得到那个空的shallowWrapper对象，我搜索了一下怀疑是jest的版本，但是即使降级也没有解决。

Answer 1

shallow( ) 确实返回了输出。 Shallow 作为渲染输出的包装器实例。你可以使用带有 debug() 的 shallow() 方法来查看打印出来的内容。如果想看渲染结果，可以在expect()方法中使用shallow().html()再测试一下。

Answer 2

我运行遇到了类似的问题，开玩笑帮助我解决了这个问题。我建议您可以清除笑话缓存，然后使用 jest --clearCache && jest -u 更新快照，然后运行您的测试。

另外，对于您的快照，我建议您使用 enzyme-to-json 序列化程序 (https://www.npmjs.com/package/enzyme-to-json) 并将您的测试修改为：

import { shallow } from 'enzyme';
import React from 'react';
import App from './App';
import { shallowToJson } from 'enzyme-to-json';

it('renders App component', () => {
  const app = shallow(<App />);
  expect(shallowToJson(app)).toMatchSnapshot();
})

shallowWrapper 为空，正在测试快照 Jest/Enzyme？

shallowWrapper is empty, testing snapshot Jest/Enzyme?

javascript

testing

jestjs

enzyme

enzyme-to-snapshot