OCMock: Make a stub do something - objective-c

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

My original answer was off-track: OCMock doesn't support this! If you wanted to change OCMock to support this, you would need to do something like adding a BOOL returnValueIsFromInvocation field to OCMockRecorder, and add a method to set this up:
- (id)andReturnResultOfInvocation:(NSInvocation *)anInvocation {
returnValueIsFromInvocation = YES;
returnValueIsBoxed = NO;
returnValueShouldBeThrown = NO;
[returnValue autorelease];
returnValue = [anInvocation retain];
return self;
}
Then teach setUpReturnValue to call the invocation (changes are in bold):
- (void)setUpReturnValue:(NSInvocation *)anInvocation
{
if (returnValueIsFromInvocation) {
NSInvocation *returnValueInvocation = (NSInvocation *)returnValue;
[returnValueInvocation invoke];
void *buffer = malloc([[anInvocation methodSignature] methodReturnLength]);
[returnValueInvocation getValue:buffer];
[anInvocation setReturnValue:buffer];
free(buffer);
}
else if(returnValueShouldBeThrown)
{
#throw returnValue;
}
else if(returnValueIsBoxed)
{
if(strcmp([[anInvocation methodSignature] methodReturnType],
[(NSValue *)returnValue objCType]) != 0)
[NSException raise:NSInvalidArgumentException
format:#"Return value does not match method signature."];
void *buffer = malloc([[anInvocation methodSignature] methodReturnLength]);
[returnValue getValue:buffer];
[anInvocation setReturnValue:buffer];
free(buffer);
}
else
{
const char *returnType = [[anInvocation methodSignature] methodReturnType];
const char *returnTypeWithoutQualifiers = returnType + (strlen(returnType) - 1);
if(strcmp(returnTypeWithoutQualifiers, #encode(id)) == 0)
[anInvocation setReturnValue:&returnValue];
}
}
This change is difficult to do by introducing subclasses because you have to override the methods that return OCMockRecorders (like stub, expect and so on) but the concrete subclasses of OCMockObject (OCClassMockObject and OCProtocolMockObject) are hidden by the framework.