"build": "babel src -d dist --ignore '**/*.test.js'",

"jest": "^23.6.0",
"babel-jest": "^23.6.0",

"test": "yarn run dist && jest"

/* globals describe test document */
import React from 'react';
import ReactDOM from 'react-dom';
import Navigation from './Base';

describe('Components', () => {
  describe('Base', () => {
    test('Render without crashing', () => {
      const div = document.createElement('div');
      ReactDOM.render(<Base />, div);
      ReactDOM.unmountComponentAtNode(div);
    });
  });
});

devServer: {
...
  historyApiFallback: {
    index: 'index.html'
  }
...
}