message: Asserted nextState is null
diff: @@ -1957,7 +1957,7 @@ describe('NavigationLinkTest', function () {
  </NavigationLink>
  </div>
  );
  - s1.renderView = ({hello}) => <h1>{hello} second</h1>
  + s1.renderView = ({hello}, nextState) => <h1>{hello} {(nextState && nextState.key) || 'second'}</h1>
  stateNavigator.navigate('s0');
  var container = document.createElement('div');
  ReactDOM.render(
  