unit testing - How to test RequestDispacher with servlet runner? -

i have the following code test, trying servlet runner starting servletunit client. fine except dispatcher.include(req,resp).it throwing exception @ dispatcher. don't know whether dispatcher working servlet runner or not.

any suggestions welcome.

requestdispatcher dispatcher1 =         getservletcontext().getrequestdispatcher("/header.jsp");     requestdispatcher dispatcher2 =         getservletcontext().getrequestdispatcher("/newclickmenu/clickmainmenu.jsp");      bufferedhttpresponsewrapper bufferedhttpresponsewrapper = new bufferedhttpresponsewrapper(res);     dispatcher1.include(req, bufferedhttpresponsewrapper);     dispatcher2.include(req, bufferedhttpresponsewrapper);