How to test heading of a react component using jest?

Question

I have a simple component which includes two buttons and the heading field. So far I tested button clicks but I want to test heading text field in the <h3> tag.

My component

class Popup extends React.Component {
    render() {
        return (
            <div className="popupOuter">
                <div className="popupInner text-center">
                    <br/>
                    <h3>{this.props.config.text}</h3>
                    <br/>
                    <div>
                    <Button type='NoButton' value={'No'} onClick={this.props.config.back} />
                    <Button type = 'YesButton' value={'Yes'} onClick={this.props.config.next}/>
                    </div>
                </div>
            </div>
        );
    }
}

My test

 test('Text test ', ()=>{
        const component = shallow(
            <Popup config={config}/>
        );
        expect(component.find('h3')).toEqual("h3");
    });

My test fails with

Error: expect(received).toEqual(expected) // deep equality Expected: "h3" Received: {}

What went wrong? Explanation pls?

Thanks.

Answer 1

.find(selector) => ShallowWrapper returns shallow wrapper, obviously, the shallow wrapper is not equal to the string h3. If you want to get the text of this h3 shallow wrapper, you need to call .text() => String on the shallow wrapper.

E.g.

index.tsx:

import React from 'react';
const Button = (props) => <button></button>;
export class Popup extends React.Component {
  render() {
    return (
      <div className="popupOuter">
        <div className="popupInner text-center">
          <br />
          <h3>{this.props.config.text}</h3>
          <br />
          <div>
            <Button type="NoButton" value={'No'} onClick={this.props.config.back} />
            <Button type="YesButton" value={'Yes'} onClick={this.props.config.next} />
          </div>
        </div>
      </div>
    );
  }
}

index.test.tsx:

import { Popup } from './';
import { shallow } from 'enzyme';

describe('60759790', () => {
  it('should render text for h3', () => {
    const mProps = { config: { text: 'h3' } };
    const wrapper = shallow(<Popup {...mProps}></Popup>);
    expect(wrapper.find('h3').text()).toEqual('h3');
  });
});

unit test results:

 PASS  stackoverflow/60759790/index.test.jsx (8.126s)
  60759790
    ✓ should render text for h3 (10ms)

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        9.418s