Ref: https://github.com/facebook/react/issues/631#issuecomment-214909216

It's a little surprising that the codepath is even being hit, maybe that's a bug too, but there should clearly be some sort of `if` check in that area.

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';
      ReactDOM.render(<span style={style}></span>, div);
      expect(console.error.argsForCall.length).toBe(2);
    });
    it('should warn about styles with numeric string values for non-unitless properties', function() {
      spyOn(console, 'error');
      var div = document.createElement('div');
      var One = React.createClass({
        render: function() {
          return this.props.inline ?
            <span style={{fontSize: '1'}} /> :
            <div style={{fontSize: '1'}} />;
        },
      });
      var Two = React.createClass({
        render: function() {
          return <div style={{fontSize: '1'}} />;
        },
      });
      ReactDOM.render(<One inline={false} />, div);
      expect(console.error.calls.length).toBe(1);
      expect(console.error.argsForCall[0][0]).toBe(
        'Warning: a `div` tag (owner: `One`) was passed a numeric string value ' +