React 0.14.7: `<option value="">empty</option>` emits empty string on change
http://jsbin.com/pisita/10/edit?html,js,console,output
React 15.0.0-rc.1`<option value="">empty</option>` emits string with value "empty" on change
http://jsbin.com/bemaze/12/edit?html,js,console,output
This is because React 15.0.0-rc.1 cuts off `value=""` from option tag

/**
 * Copyright 2013-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @emails react-core
 */
'use strict';
var emptyFunction = require('emptyFunction');
describe('ReactDOMInput', function() {
  var EventConstants;
  var React;
  var ReactDOM;
  var ReactDOMFeatureFlags;
  var ReactLink;
  var ReactTestUtils;
  var inputValueTracking;
  function setUntrackedValue(elem, value) {
    var tracker = inputValueTracking._getTrackerFromNode(elem);
    var current = tracker.getValue();
    elem.value = value;
    tracker.setValue(current);