componentDidMount中使用的setState值未反映在酶测试中

Question

Component.js

import React from 'react'
import request from 'superagent'

export default React.createClass({
    getInitialState() {
        return {cats: []}
    },

    componentDidMount() {
        request('/api', (err, res) => {
            if (err) return;
            this.setState({
                cats: res.body.results
            })
        })
    },

    render() {
        let cats = this.state.cats
        let catsList = (
            <ul>
                {cats.map((c) => <li key={c.id}>cat</li>)}
            </ul>
        )
        return (
            <div>
                {cats.length ? catsList : null}
            </div>
        )
    }
})

Component.test.js

jest.unmock('../app.js')
jest.unmock('superagent')

import React from 'react'
import {mount} from 'enzyme'
import nock from 'nock'
import App from '../app.js'

describe('App', () => {
    let ajaxFn
    beforeEach(() => {
        ajaxFn = nock('http://localhost')
            .get('/api')
            .reply(200, {
                results: [{id: 1}, {id: 2}, {id: 3}]
            })
    })

    it('renders correct number of cats', () => {
        let wrapper = mount(<App />)
        expect(wrapper.state('cats').length).toBe(3)
    })
})

测试没有通过.wrapper.state('cats').length永远0.

我明白setState不保证立即更新状态,但是如果我在组件中记录'cats',我可以看到它更新.

Answer 1

如果您最终在某个酶不知道的上下文中设置了组件中的状态,则必须手动调用.update()包装器才能获得渲染树的更新版本.

it('renders correct number of cats', () => {
    let wrapper = mount(<App />)
    expect(wrapper.update().state('cats').length).toBe(3)
})