在从命令行在 Jest 中测试 React 应用程序时使用 Enzyme 的 mount
函数时,我收到以下错误。它说没有加载 DOM 环境,我认为这意味着我需要设置 JSDOM。然而,JSDOM似乎附带了Jest,并根据Facebook的Jest文档进行了预配置。这是我的测试:
import React from 'react'
import MyComponent from '../src/components/MyComponent'
import { configure } from 'enzyme'
import Adapter from 'enzyme-adapter-react-16'
import { mount, shallow } from 'enzyme'
import { Menu, Dropdown, Modal } from 'semantic-ui-react'
import renderer from 'react-test-renderer';
configure({ adapter: new Adapter() })
test('it works', () => {
const wrapper = mount(
<MyComponent />
)
expect(wrapper.contains('foobar')).toEqual(true)
});
这是错误:
Enzyme's mount expects a DOM environment to be loaded, but found none
at assertDomAvailable (node_modules/enzyme-adapter-utils/build/Utils.js:107:11)
at ReactSixteenAdapter.createMountRenderer (node_modules/enzyme-adapter-react-16/build/ReactSixteenAdapter.js:203:52)
at ReactSixteenAdapter.createRenderer (node_modules/enzyme-adapter-react-16/build/ReactSixteenAdapter.js:384:25)
at new ReactWrapper (node_modules/enzyme/build/ReactWrapper.js:96:54)
at mount (node_modules/enzyme/build/mount.js:19:10)
at Object.<anonymous> (test/LinesheetModal.test.js:12:37)
at new Promise (<anonymous>)
它似乎与酶-适配器-反应-16有关。知道可能出了什么问题吗?
看起来问题是JSDOM和Enzyme没有正确设置。将此文件作为预加载文件添加到 Jest 修复了它:
import Adapter from 'enzyme-adapter-react-16'
import { configure } from 'enzyme'
import jsdom from 'jsdom'
function setUpDomEnvironment() {
const { JSDOM } = jsdom;
const dom = new JSDOM('<!doctype html><html><body></body></html>', {url: 'http://localhost/'});
const { window } = dom;
global.window = window;
global.document = window.document;
global.navigator = {
userAgent: 'node.js',
};
copyProps(window, global);
}
function copyProps(src, target) {
const props = Object.getOwnPropertyNames(src)
.filter(prop => typeof target[prop] === 'undefined')
.map(prop => Object.getOwnPropertyDescriptor(src, prop));
Object.defineProperties(target, props);
}
setUpDomEnvironment();
configure({ adapter: new Adapter() })
Jest 配置了开箱即用的 JSDom,您需要确保在配置中使用 testEnvironment: jsdom
。
添加到您的开玩笑配置中:
{
testEnvironment: 'jsdom',
verbose: true,
testURL: 'http://localhost/',
}
更新:我又一次遇到了这个 - 我在 describe() 函数上使用了 async 关键字
正如我在 https://github.com/airbnb/enzyme/issues/1558 上提到的,当我遇到这个问题时,这是由于比我应该更早地传递和执行done()
。
就我而言,我在测试中错过了以下导入:
import 'node_modules/jsdom-global/register'