it('should support onKeyDown', function() {
      var mockKeyDown = sinon.spy();
      var view = TestUtils.renderIntoDocument(<TestComponent value="" onChange={mockOnChange} items={items} onKeyDown={mockKeyDown} />);
      var input = TestUtils.findRenderedDOMComponentWithTag(view, 'input');
      TestUtils.Simulate.keyDown(input, { keyCode: KEY_CODE_COMMA });