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I am interested in using General/OCMock but there is little documentation and I am unsure of how to begin. I have been using General/OCUnit successfully. The reason I think I need to use mock objects is that I am designing an object that will function in response to user input. I want the object (functioning as a controller) I am going to test to present some choice to the user, then respond to the user’s choice by manipulating model objects. I want to be able to tell the object what the user’s choices were and then test what it will do based on these choices. I think I need a General/MockObject to substitute for the view object.Can anyone point me to a useful tutorial or at least post a few hints? —-Martin Fowler has a very good article on Mock Objects here: Basically, you’re right - if you want to test that a controller properly interacts with a view - without actually using the view, than Mock Objects are a good way to go.–General/TimHart!

Original Poster (or anybody else): Have you had success? Anybody care to write up a brief HOWTO for General/OCMock? I’m in the same boat. Or, how about a more concrete question: I’m trying to mock an object that is a delegate for another object, to make sure that the appropriate messages get passed to the delegate. I have an informal protocol in the object that sends the delegate messages (the protocol is on General/NSObject). I don’t have any classes that “implement” this informal protocol - that’s for people who use my framework to do. So how can I create a mock object that responds to the message? When I try something like:

// I’ve declared an informal protocol in General/MYObject.h on General/NSObject, called General/MYInformalProtocol General/MYObject *mo = General/[[MYObject alloc] init]; General/OCMockObject *delegateMock = General/[OCMockObject General/MYInformalProtocol];

[mo setDelegate:delegateMock]; General/delegateMock expect] myDelegateMessage:mo];

[mo myMessage];

[delegateMock verify];

I get an error: error: -[[[MYTestTarget myTestName]: *** -General/[NSProxy methodSignatureForSelector:] called!. I assume that this is because General/MYObject checks whether its delegate responds to myDelegateMessage before sending the message. Is there a good way to do this? Do I need to create a formal protocol for classes to use as a delegate??

A request for General/OCMock (posted here, because I don’t see any way to contact the author on General/OCMock’s site): allow andReturn: (or some similar method) to return BOOL values. NO works (by chance, because 0=NO=nil), but YES doesn’t work. Generally, it would be useful to andReturn:YES, and specifically when I’m using delegates. I cannot mock a delegate object because the code checks whether or not the delegate respondsToSelector:, which needs to return YES, which I can’t do in my mock object. So I can’t test code that has delegates with General/OCMock (at least not test whether they properly call the delegate). —- Values such as YES are supported but you have to specify them with OCMOCK_VALUE, eg. General/[myMock expect] andReturn:OCMOCK_VALUE(YES)] foo] —- Actually, that won’t quite work. You cannot pass something other than a variable into OCMOCK_VALUE. So the boolean would have to look like this:

BOOL no = NO; [[[myMock expect] andReturn:OCMOCK_VALUE(no)] haveYouGotAnyLimburger];

To the above poster, you have to get the mock object as follows:

[[OCMockObject *delegateMock = General/[OCMockObject mockForClass:General/[NSObject class]];

The General/OCMock homepage at Mulle Kybernetik now has a how-to and contact details, even a mailing list.