jestsetup.js
function copyProps(src, target) {
  const props = Object.getOwnPropertyNames(src)
    .filter(prop => typeof target[prop] === 'undefined')
    .reduce((result, prop) => R.merge(
      result,
      {
        [prop]: Object.getOwnPropertyDescriptor(src, prop)
      }),
      {});
  Object.defineProperties(target, props);
}
function copyProps(src, target) {
  const props = Object.getOwnPropertyNames(src)
    .filter(prop => typeof target[prop] === 'undefined')
    .reduce((result, prop) => R.merge(
      result,
      {
        [prop]: Object.getOwnPropertyDescriptor(src, prop)
      }),
      {});
  Object.defineProperties(target, props);
}
jsdom, window, document, navigator setup http://airbnb.io/enzyme/docs/guides/jsdom.html