CODEWITHSUNDEEP
unit-testingtestingreactjssnapshotjestjs
Umang Gupta
Umang Gupta

Reputation: 16480

React Snapshot testing with jest - Failed prop type: Invalid prop `children` of type `string` supplied

I am trying to test a pure react component.

Component

import React, {Component} from 'react';

class App extends Component {
    constructor (props){
        super(props);
        props.init();
    }

    render() {
        return (
            <div className="container-wrapper">
                {this.props.children}
            </div>
        );
    }
}

App.propTypes = {
    init : React.PropTypes.func,
    children : React.PropTypes.element,
};
export default App;

Jest Snapshot Test

import React from 'react';
import App from 'app/main/components/App';
import renderer from 'react-test-renderer';

jest.mock('react-dom');
const blank = jest.fn();
describe('App', () => {
    it('Renders App', () => {
        const component = renderer.create(<App init={blank}> </App>);
        const tree = component.toJSON();
        expect(tree).toMatchSnapshot();
    });
});

When I execute the test I get below error. 

 console.error node_modules/fbjs/lib/warning.js:36
      Warning: Failed prop type: Invalid prop `children` of type `string` supplied to `App`, expected a single ReactElement.
          in App

I can understand that is says Props.children is invalid. How can I mock props.children? Or is there some other way test such components

Upvotes: 0

Views: 1713

Answers (2)

Black
Black

Reputation: 10407

The previous solution still returns string. You can return any HTML element instead

it('Renders App', () => {
  const component = renderer.create(
    <App init={blank}>
      <div />
    </App>
  );
  const tree = component.toJSON();
  expect(tree).toMatchSnapshot();
});

Upvotes: 1

Richard Scarrott
Richard Scarrott

Reputation: 7073

You can simply pass a child to your <App /> component:

it('Renders App', () => {
    const component = renderer.create(
        <App init={blank}>
            Hello App.
        </App>
    );
    const tree = component.toJSON();
    expect(tree).toMatchSnapshot();
});

Upvotes: 2

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