Testing components with Jest fails

问题:

I am new to Jest and Java Script in general. I wrote a test to one of my components but it seems to fail and I can't figure out how to fix it and what is wrong (Apparently something with enzyme).

It prints:

● Console

    console.log src/App.js:18
      props = {}
    console.log src/App.js:19
      url = ./api/user/undefined/

C:\Users\Itay\Documents\Matan - Microsoft\Matan\MatanClient\node_modules\react-dom\cjs\react-dom.development.js:62
    throw error;
    ^

Invariant Violation: The `document` global was defined when React was 
initialized, but is not defined anymore. This can happen in a test 
environment if a component schedules an update from an asynchronous 
callback, but the test has already finished running. To solve this, you can 
either unmount the component at the end of your test (and ensure that any 
asynchronous operations get canceled in `componentWillUnmount`), or you can 
change the test itself to be asynchronous.

The test I wrote was as simple as I could:

import React from 'react';
import PropTypes from 'prop-types';
import { shallow, configure } from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';
import { AdminViewComponent } from '../components/AdminViewComponent.js';

configure({ adapter: new Adapter() });

describe('<AdminViewComponent />', () => {
  it('renders an admin view', () => {
  const admin = shallow(<AdminViewComponent />);
  expect(admin.render()).toBeCalled;
  });
}); 

And the component itself looks like this:

import React, { Component } from 'react';
import PropTypes from 'prop-types';
import {Typeahead} from 'react-bootstrap-typeahead'; // ES2015
import axios from 'axios';
import {WholeScreen} from './WholeScreenComponent.js';

export class AdminViewComponent extends Component{

  constructor(props) {
    super(props);

    this.state = {
      emailList: [],
      selectedUser: "",
      SelectedUserDonationData:{}
    };

    this._handleChange = this._handleChange.bind(this);
  }

 getInitialState(){
    return {
      // [{}] is weird, either use undefined (or [] but undefined is better).
      // If you use [], you loose the information of a "pending" request, as 
      // you won't be able to make a distinction between a pending request, 
      // and a response that returns an empty array
      emailList: undefined,
      selectedUser: undefined,
      SelectedUserDonationData:undefined
    } 
  }
  componentDidMount(){
    this.setState({emailList : undefined});
    return axios.get('./api/user/', {
        headers: {
            'Content-Type': 'application/json',
            'Authorization': 'Bearer '+ this.props.token
        }
        }).then(response => {
            const emailListResult = response.data;
            this.setState({ emailList : emailListResult });

        }).catch(function (error) {
              console.log(error);
        });
  }

  _handleChange(SelectedUser){
     this.setState({ selectedUser : SelectedUser, selectedUserDonationData: undefined });


    axios.get('./api/user/' + SelectedUser + '/' , 
       {headers: {
            'Content-Type': 'application/json',
            'Authorization': 'Bearer '+ this.props.token
        }
        }).then(response => {
            const selectedUserDonationDataResponse = response.data;
            this.setState({ selectedUserDonationData : selectedUserDonationDataResponse });
            console.log(selectedUserDonationDataResponse);

        }).catch(function (error) {
              console.log(error);
        });

  }

    render() {
      var adminView;
      if (!this.state.emailList){
        adminView = <div> Please wait while we retrive all users... </div>
      }
      else{
        adminView =<div> <div> Please select user to show his/her donations </div>        
                    <Typeahead 
                      placeholder="Select user email..."
                      onChange={this._handleChange}
                      options={this.state.emailList}/> </div>;
      }

      var selectedUserData;
      if (this.state.selectedUserDonationData){

        selectedUserData = <div className="AdminViewData"> 
                          <h4 className="DtatOf">Showing donations of : {this.state.selectedUser}</h4>
                              <WholeScreen  data={this.state.selectedUserDonationData.DonationsList}/>
                        </div>
      }

      var url = "./api/user/" ; 
      return(
      <div className="AdminView">

          {adminView}              
          {selectedUserData}

      </div>          
      );
    }
}

Thanks is advance!

回答1:

I believe your shallow renderer import should look like this:

import { shallow, configure  } from 'enzyme';

EDIT: could you add the following import and initialization below your shallow renderer.

import Adapter from 'enzyme-adapter-react-16';

configure({ adapter: new Adapter() });

As stated in the Enzyme docs as well: enzyme installation