如何测试 React ErrorBoundary

a.b*_*eri 9 testing unit-testing reactjs enzyme

React 的新手,但不是测试应用程序。

我想确保每次组件抛出错误时都会显示 ErrorBoundary 消息。如果你不知道我所说的 ErrorBoundary 是什么意思,这里是一个链接

我正在使用Mocha + Chai + Enzyme

假设我们需要使用以下测试配置来测试React 计数器示例

测试配置

// DOM
import jsdom from 'jsdom';
const {JSDOM} = jsdom;
const {document} = (new JSDOM('<!doctype html><html><body></body></html>')).window;
global.document = document;
global.window = document.defaultView;
global.navigator = global.window.navigator;

// Enzyme
import { configure } from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';
configure({ adapter: new Adapter() });

// Chai
import chai from 'chai';
import chaiEnzyme from 'chai-enzyme';
chai.use(chaiEnzyme());
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更新 1 - 一些后来的想法

在阅读了有关连接组件的最佳测试方法(涉及类似问题)的对话后,我知道我不必担心componentDidCatch捕获错误。React 已经过足够的测试,确保无论何时抛出错误都会被捕获。

因此只有测试两个测试:

1:如果有任何错误,请确保 ErrorBoundary 显示消息

// error_boundary_test.js
import React from 'react';
import { expect } from 'chai';
import { shallow } from 'enzyme';

import ErrorBoundary from './some/path/error_boundary';

describe('Error Boundary', ()=>{
    it('generates a error message when an error is caught', ()=>{
        const component = shallow(<ErrorBoundary />);
        component.setState({
            error: 'error name', 
            errorInfo: 'error info'
        });
        expect(component).to.contain.text('Something went wrong.');
    });
});
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2:确保组件包含在 ErrorBoundary 中(在React 计数器示例中<App />,这是误导性的。想法是在最近的父组件上执行此操作)。

注意:1)它需要在父组件上完成,2)我假设子组件是简单的组件,而不是容器,因为它可能需要更多的配置。进一步的想法:这个测试可以更好地使用parent而不是descendents......

// error_boundary_test.js
import React from 'react';
import { expect } from 'chai';
import { shallow } from 'enzyme';

import App from './some/path/app';

describe('App', ()=>{
    it('wraps children in ErrorBoundary', ()=>{
        const component = mount(<App />);
        expect(component).to.have.descendants(ErrorBoundary);
    });
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Kri*_*iti 8

使用 React 测试库测试 ErrorBoundary 组件

const Child = () => {
  throw new Error()
}

describe('Error Boundary', () => {
  it(`should render error boundary component when there is an error`, () => {
    const { getByText } = renderProviders(
      <ErrorBoundary>
        <Child />
      </ErrorBoundary>
    )
    const errorMessage = getByText('something went wrong')
    expect(errorMessage).toBeDefined()
  })
})
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渲染提供者

import { render } from '@testing-library/react'

const renderProviders = (ui: React.ReactElement) => render(ui, {})
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  • 什么是“renderProviders”以及为什么需要它? (3认同)

wjs*_*jsc 6

这是我没有设置组件状态的尝试:

错误边界:

import React, { Component } from 'react';
import ErroredContentPresentation from './ErroredContentPresentation';

class ContentPresentationErrorBoundary extends Component {
  constructor(props) {
    super(props);
    this.state = { hasError: false };
  }

  componentDidCatch(error, info) {
    this.setState({ hasError: true });
  }

  render() {
    return this.state.hasError ? <ErroredContentPresentation /> : this.props.children;
  }
}

export const withErrorBoundary = WrappedComponent =>
  props => <ContentPresentationErrorBoundary>
            <WrappedComponent {...props}/>
          </ContentPresentationErrorBoundary>;
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和测试:

it('Renders ErroredContentPresentation Fallback if error ', ()=>{
  const wrappedComponent = props => {
    throw new Error('Errored!');
  };
  const component = withErrorBoundary( wrappedComponent )(props);
  expect(mount(component).html()).toEqual(shallow(<ErroredContentPresentation/>).html());
});
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