Question

我正在使用Jest和Enzyme来测试React组件，但是我发现很难测试一个简单的无状态组件，该组件由地图javascript函数的结果组成。

MovieCard.js 组件：

import React from 'react'
import PropTypes from 'prop-types'

const MovieCard = ({ resultsForSubmit }) =>
  (
    resultsForSubmit.map(r => (
      <article className="card" key={r.imdbID}>
        <a href={r.Poster}>
          <picture className="thumbnail">
            <img src={(r.Poster !== "N/A")? r.Poster : "src/assets/not-found.png"} alt={r.Title} />
          </picture>
        </a>
        <div className="card-content clearfix">
          <div className="review">
            <h2>{r.Title}</h2>
            <p>{r.Type}</p>
          </div>
          <div className="reviewer">
          </div>
        </div>
      </article>
    )
    )
  )

export default MovieCard;

MovieCard.propTypes = {
  resultsForSubmit: PropTypes.array,
}

MovieCard.test.js

import React from 'react'
import { mount  } from 'enzyme'
import MovieCard from './MovieCard';

describe('<MovieCard /><MovieCard />', () => {
    const data = [
        { imdbId: '2', Poster: 'poster2', Title: 'title2', Type: 'type2' }
    ];

    it('renders 2 <MovieCard /> components', () => {
        mount(<MovieCard data={ data } />);
    });
})

运行测试时，显示此错误：

**<MovieCard /><MovieCard /> › renders 2 <MovieCard /> components

    TypeError: Cannot read property 'map' of undefined

      4 | const MovieCard = ({ resultsForSubmit }) =>
      5 |   (
    > 6 |     resultsForSubmit.map(r => (
        |                      ^
      7 |       <article className="card" key={r.imdbID}>
      8 |         <a href={r.Poster}>
      9 |           <picture className="thumbnail">**

目前，我只想测试组件是否已渲染，但是我愿意在其上使用其他测试功能。

Answer 1

<MovieCard />需要一个道具resultsForSubmit，而您在测试中通过了data。

尝试这样的方法：

MovieCard.test.js

describe('<MovieCard />', () => {
  const resultsForSubmit = [
    { imdbId: '1', Poster: 'poster1', Title: 'title1', Type: 'type1' },
    { imdbId: '2', Poster: 'poster2', Title: 'title2', Type: 'type2' }
  ];
  let movieCard; 

  beforeEach(() => {
    movieCard = shallow(<MovieCard resultsForSubmit={resultsForSubmit} />);
  });

  it('renders 2 articles', () => {
    expect(movieCard.find('article').length).toBe(2);
  });
})

使用地图函数返回的Jest和Enzyme测试React组件

1 个答案: