React-bootstrap Typeahead不适用于Jest快照 [英] React-bootstrap Typeahead does not work with Jest snapshots

问题描述

我有一个来自API文档的非常简单的 AsyncTypeahead 示例:

I have a very simple AsyncTypeahead example from the API documentation :

    import {AsyncTypeahead} from "react-bootstrap-typeahead";
    import React, {Component} from "react";

    class AsyncTest extends Component<Props, State> {
        constructor() {
            super()
            this.state = {
                isLoading:false,
                options:{}
            }
        }
        render() {
            return <AsyncTypeahead
                disabled={true}
                isLoading={this.state.isLoading}
                onSearch={query => {
                    this.setState({isLoading: true});
                    fetch(`https://api.github.com/search/users?q=123`)
                        .then(resp => resp.json())
                        .then(json => this.setState({
                            isLoading: false,
                            options: json.items,
                        }));
                }}
                options={this.state.options}
            />
        }
    }

export default AsyncTest;

现在，如果我想为此组件创建一个Jest快照测试，那么我将编写如下内容:

Now if I want to create a Jest snapshot test of this component then I would write something like this :

import React from 'react';
import renderer from "react-test-renderer";
import AsyncTest from "./AsyncTest";

describe('Async Test', () => {
    test('test', () => {
        const test= <AsyncTest/>
        expect(renderer.create(test).toJSON()).toMatchSnapshot();
    });
});

这不起作用.我收到此错误:

This does not work. I get this error :

TypeError:无法读取null的属性样式"

TypeError: Cannot read property 'style' of null

at Window.getComputedStyle (A:\frontend\node_modules\jest-environment-jsdom\node_modules\jsdom\lib\jsdom\browser\Window.js:524:20)
at copyStyles (A:\frontend\node_modules\react-bootstrap-typeahead\lib\containers\hintContainer.js:61:27)
at HintedInput.componentDidMount (A:\frontend\node_modules\react-bootstrap-typeahead\lib\containers\hintContainer.js:113:9)
at commitLifeCycles (A:\frontend\node_modules\react-test-renderer\cjs\react-test-renderer.development.js:10930:22)

这是bootstrap typeahead的已知问题吗?

Is this a known issue with bootstrap typeahead?

推荐答案

遇到了同样的问题，这就是我的解决方案. 罪魁祸首是预先输入的提示容器，具体来说就是以下功能:

Had the same problem and this was my solution. Culprit is the Hintcontainer of typeahead and specifically this function:

function copyStyles(inputNode, hintNode) {
  var inputStyle = window.getComputedStyle(inputNode);
  /* eslint-disable no-param-reassign */

  hintNode.style.borderStyle = interpolateStyle(inputStyle, 'border', 'style');
  hintNode.style.borderWidth = interpolateStyle(inputStyle, 'border', 'width');
  hintNode.style.fontSize = inputStyle.fontSize;
  hintNode.style.lineHeight = inputStyle.lineHeight;
  hintNode.style.margin = interpolateStyle(inputStyle, 'margin');
  hintNode.style.padding = interpolateStyle(inputStyle, 'padding');
  /* eslint-enable no-param-reassign */
}

createMockNode的问题:inputNode中的样式不是常见的对象，而是 CSSStyleDeclaration，并且我没有费心去完全模拟它.
https://developer.mozilla.org/zh-CN/docs/Web/API/CSSStyleDeclaration

Problem with createMockNode: Styles from the inputNode are not a common object, but a CSSStyleDeclaration, and I did not bother to mock this completely.
https://developer.mozilla.org/en-US/docs/Web/API/CSSStyleDeclaration

因此，当与一个公共对象交换出去时，使用window.getComputedStyle不起作用. 对我来说，最简单的解决方案就是模拟window.getComputedStyle. 因此，第一部分是模拟触发错误的getComputedStyle函数.

So, using window.getComputedStyle does not work when swapped out with a common object. Most simple solution to me, was to mock window.getComputedStyle, too. So, First part is to mock the getComputedStyle function which is triggering the error.

global.window.getComputedStyle = jest.fn(x=>({}));

但是仍然需要 createNodeMock 为输入节点提供一个空的样式对象.

But createNodeMock is still needed to provide an empty style object for the input node.

TLDR；快照适用于此代码段

   global.window.getComputedStyle = jest.fn(x=>({}));
        const createNodeMock = (element) => ({
                style: {},
        });
   const options={createNodeMock};
   const tree = renderer
            .create(form,options)
            .toJSON();

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