add jsdom; add basic Avatar component test

spec/javascript/components/avatar.test.jsx

@@ -0,0 +1,12 @@
+import { expect } from 'chai';
+import { render } from 'enzyme';
+
+import Avatar from '../../../app/assets/javascripts/components/components/avatar'
+
+describe('<Avatar />', function() {
+  it('renders an img with the given src', function() {
+    const src = '/path/to/image.jpg';
+    const wrapper = render(<Avatar src={src} size={100} />);
+    expect(wrapper.find(`img[src="${src}"]`)).to.have.length(1);
+  });
+});

spec/javascript/components/loading_indicator.test.jsx

@@ -1,7 +1,5 @@
 import { expect } from 'chai';
 import { shallow } from 'enzyme';
-import React from 'react';
-global.React = React;
 
 import LoadingIndicator from '../../../app/assets/javascripts/components/components/loading_indicator'
 

spec/javascript/setup.js

@@ -0,0 +1,22 @@
+/**
+ * http://airbnb.io/enzyme/docs/guides/jsdom.html
+ */
+var jsdom = require('jsdom').jsdom;
+
+var exposedProperties = ['window', 'navigator', 'document'];
+
+global.document = jsdom('');
+global.window = document.defaultView;
+Object.keys(document.defaultView).forEach((property) => {
+  if (typeof global[property] === 'undefined') {
+    exposedProperties.push(property);
+    global[property] = document.defaultView[property];
+  }
+});
+
+global.navigator = {
+  userAgent: 'node.js'
+};
+
+var React    = window.React    = global.React    = require('react');
+var ReactDOM = window.ReactDOM = global.ReactDOM = require('react-dom');