Mocking a component constructor with Jest

App.mockImplementation.test.js

// An answer for this stackoverlow question: https://stackoverflow.com/questions/48831701/jest-how-to-mock-default-export-component-when-same-module-also-has-named-expor

import React from 'react';
import { shallow } from 'enzyme';
import App, { myUtilityFunction } from './App';

jest.mock('./App');

App.mockImplementation(() => {
    return {
        render: () => <div>MockApp</div>
    };
});
myUtilityFunction.mockImplementation(() => 'foo');

it('renders the mock React component', () => {
    /**
     * PASSES
     */
    expect(shallow(<App />).getElement()).not.toEqual(null);
});

it('runs the utility method correctly', () => {
    /**
     * PASSES
     */
    expect(myUtilityFunction()).toEqual('foo');
})