OCMock: Make a stub do something

Question

I'm getting used to OCMock. Coming from a Java/JMock background I'm now looking for the ability to say [[[myMock stub] returnValueFromCustomMethod] someMockedMethod]; where returnValueFromCustomMethod is defined in the test class. I was originally thinking something along the terms of [[[myMock stub] usingSelector:@selector(myMethod:)] someMockedMethod]; but after writing I wonder if my first approach makes more sense. Either way, could someone show me if and how this can be done?

Answer 1

That's pretty close to what I'm looking for! Stil there's a lot of noise in the code. I tried a mix of your suggestion along with another approach but I seem to be off by one.

@interface OCMockRecorder (CustomMethods)
- (id) andPerformsSelector:(SEL)selector onTargetObject:(id)targetObject;
@end

@implementation OCMockRecorder (CustomMethods)

- (id) andPerformsSelector:(SEL)selector onTargetObject:(id)targetObject
{
    NSMethodSignature *signature = [[targetObject class] instanceMethodSignatureForSelector:selector];

    // set up an invocation equivalent to [self customMethod]
    NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:signature];
    [invocation setTarget:targetObject];
    [invocation setSelector:selector];

    // introduce it into the mock
    [self setUpReturnValue:invocation];
    return nil;
}

@end

Then to test I use:

@interface OCMockExtensionsTest : SenTestCase
{
    BOOL methodWasCalled;
}

-(void) willBeCalledOnBehalfOfMock;

@end

@implementation OCMockExtensionsTest

-(void) willBeCalledOnBehalfOfMock
{
    methodWasCalled = YES;
}

-(void) setUp
{
    methodWasCalled = NO;
}

-(void) testOCMockExtensions
{
    NSString* aMock = [OCMockObject mockForClass:[NSString class]];
    [[ [(id)aMock stub] andPerformsSelector:@selector(willBeCalledOnBehalfOfMock) onTargetObject:self] 
    initWithString:OCMOCK_ANY];
    STAssertFalse(methodWasCalled, @"Method should not be called until after the mocked method is invoked.");
    [aMock initWithString:@"Hello World!"];
    STAssertTrue(methodWasCalled, @"Method SHOULD be called after the mocked method is invoked.");
}


@end

Yet I see the error: error: OCMockObject[NSString]: unexpected method invoked: initWithString:@"Hello World!" stubbed: (null) Which tells me my invocation isn't being matched.