Enzyme expects an adapter to be configured

Question

I created a new React application by create-react-app and I wanted to write a unit test to a component named "MessageBox" that I created in the application. This is the unit test that I wrote:

import MessageBox from "../MessageBox";
import { shallow } from 'enzyme';
import React from 'react';

test('message box', () => {
   const app = {setState: jest.fn()};
   const wrapper = shallow(<MessageBox app={app}/>);
   wrapper.find('button').at(0).simulate('click');
   expect(app.setState).toHaveBeenLastCalledWith({modalIsOpen: false});
});

I also added a file under 'src' folder named 'setupTests.js' with the content:

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

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

I ran it by:

npm test

and I got the error:

Enzyme Internal Error: Enzyme expects an adapter to be configured, but found none. To configure an adapter, you should call Enzyme.configure({ > adapter: new Adapter() })

Do you know what can solve this problem?

Answer 1

Add it to your test case file.

import React from 'react';
import Adapter from 'enzyme-adapter-react-16';
import { shallow, configure } from 'enzyme';

configure({adapter: new Adapter()});
test('message box', ()=> {
     ...
})