Can't run unit tests with Jest

[andrekovac]

While running a most simple unit test I get TypeError: Cannot read property 'IsAndroid' of undefined as in issue #36 . However, building and running the app works perfectly fine.

Mocking react-native-sound via jest.mock('react-native-sound'); doesn't help.

Here's my unit test code:

import 'react-native';
import React from 'react';
import renderer from 'react-test-renderer';

jest.mock('react-native-sound');

import myComponentWithANestedSubComponentWhichUsesRNSound from './';

describe('<ListItemVideo />', () => {

  it('renders correctly', () => {
    const tree = renderer.create(<myComponentWithANestedSubComponentWhichUsesRNSound />);
  });
});

[trepidity]

duplicate of #245