The only React.js component test you'll ever need (Enzyme + Chai)

my-component.spec.js

import React from 'react';
import { shallow } from 'enzyme';
import MyComponent from '../src/my-component';

const wrapper = shallow(<MyComponent/>);

describe('(Component) MyComponent', () => {
  it('renders without exploding', () => {
    expect(wrapper).to.have.length(1);
  });
});

For those of us using Jest, you would check the length with expect(wrapper).toHaveLength(1)

@chiedo Does it do that? I'm not seeing where this happens.

For those in 2018 using create-react-app: https://github.com/facebook/create-react-app/blob/master/packages/react-scripts/template/README.md#testing-components

tl;dr; use:

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';

it('renders without crashing', () => {
  const div = document.createElement('div');
  ReactDOM.render(<App />, div);
});