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

var style = {border: '1px solid black'};
      var App = React.createClass({
        getInitialState: function() {
          return {style: style};
        },
        render: function() {
          return <div style={this.state.style}>asd</div>;
        },
      });
      var stub = ReactTestUtils.renderIntoDocument(<App />);
      style.position = 'absolute';
      stub.setState({style: style});
      expect(console.error.argsForCall.length).toBe(1);
      expect(console.error.argsForCall[0][0]).toEqual(
        'Warning: `div` was passed a style object that has previously been ' +
        'mutated. Mutating `style` is deprecated. Consider cloning it ' +
        'beforehand. Check the `render` of `App`. Previous style: ' +
        '{border: "1px solid black"}. Mutated style: ' +
        '{border: "1px solid black", position: "absolute"}.'
      );
      style = {background: 'red'};
      stub = ReactTestUtils.renderIntoDocument(<App />);
      style.background = 'green';
      stub.setState({style: {background: 'green'}});
      
      expect(console.error.argsForCall.length).toBe(1);
      style = {background: 'red'};
      var div = document.createElement('div');
      ReactDOM.render(<span style={style}></span>, div);
      style.background = 'blue';