flex - asmock Previous method requires a return value or an exception to throw -

trying head around asmock implement unit testing in project. want test mainmediator , since there objects created in mainmediator onregister call, i'm thinking should mock objects. that's correct begin with!

i have this

 [rule] public var includemocks : includemocksrule = new includemocksrule([     ieventdispatcher, imyservice  ]);   [before]  public function setup():void {     mockrepository = new mockrepository();     mainview = new mainview();     mainmediator = new mainmediator();      dispatcher = ieventdispatcher(mockrepository.createstub(ieventdispatcher, stuboptions.none));     myservice = imyservice(mockrepository.createstub(imyservice, stuboptions.none));     mockrepository.stubevents(dispatcher);      setupresult.forcall(chatservice.clientid)               .returnvalue("");      mockrepository.replayall();      mainmediator.eventdispatcher = dispatcher;     myservice.eventdispatcher = dispatcher;        mainmediator.service = myservice;        ....      mainmediator.onregister();  } 

when step through test , stop @ mockrepository.stubevents(dispatcher). can see errors in myservice class error: previous method imyservice/clientid/get(); requires return value or exception throw. clientid happens first property hence why it's being picked on.

i thought either stuboptions.none mean no properties stubbed or setupresult.forcall(myservice.clientid) fix none did.

answering question in comment re: eventdispatcher, have:

myservice extends servicebase implements imyservice

where servicebase extends actor

i found need following in imyservice access eventdispatcher.

function eventdispatcher():ieventdispatcher; function set eventdispatcher(dispatcher:ieventdispatcher):void; 

not sure if correct. bit confused now.

can please tell me i'm going wrong? thanks!

this common problem when mocking concrete classes, rather interfaces: if constructor calls method (or property getter), return null because hasn't been mocked yet.

there's not anyway workaround it, except abstract class through interface , mock that.