React component + Jest/Enzyme test

MyComponent.js

import React from 'react';
import MyButton from './MyButton';

export default function MyComponent(props) {
  return (<div>Hello, world! <MyButton>Click Here</MyButton></div>);
}

MyComponent.test.js

/* eslint-env jest */

import React from 'react';
import Enzyme, { mount } from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';
import MyComponent from './MyComponent';
import MyButton from './MyButton';

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

test('it renders without crashing', () => {
  mount(<MyComponent />);
});
  
test('it contains a MyButton component', () => {
  const wrapper = mount(<MyComponent />);
  expect(wrapper.find(MyButton)).toHaveLength(1);
});