[chore] added test for default parentSelector.
[chore] added test for default parentSelector.

rackt/react-modal,diasbruno/react-modal,bluSCALE4/react-modal,springload/react-modal,bluSCALE4/react-modal,reactjs/react-modal,springload/react-modal,reactjs/react-modal,springload/react-modal,diasbruno/react-modal,rackt/react-modal,bluSCALE4/react-modal,diasbruno/react-modal,reactjs/react-modal