How to properly stub methods on a different thread using OCMock? - objective-c

Question

I have the following unit test that is failing. I think its because OCMock does not work well across multiple threads but I could be wrong. mockTestMethodA never gets called. If I modified the code to call the testMethodA on the same thread (without NSThread), stubbing seems to work. Is this a known limitation of OCMock or am I missing something?
Sample code:
- (void) testCallMethodUsingNSThreadFromADifferentClass
{
mockTestClassA = [OCMockObject partialMockForObject:testClassA];
[[[mockTestClassA expect] andCall:#selector(mockTestMethodA) onObject:self] testMethodA];
[testClassC threadedRequestToCallMethodA];
[self waitForCompletion:5.0];
[mockTestClassA verify];
}
threadedRequestToCallMethodA and callMethodAFromTestClassC in TestClassC are defined as follows:
- (void) threadedRequestToCallMethodA
{
[NSThread detachNewThreadSelector:#selector(callMethodAFromTestClassC) toTarget:self withObject:nil];
}
- (void) callMethodAFromTestClassC
{
[[[TestClassA alloc] init] testMethodA];
}
testMethodA in TestClassA is defined as:
- (void) testMethodA
{
NSLog(#"testMethodA");
}
Stub method is defined as follows:
- (void) mockTestMethodA
{
NSLog(#"mockTestMethodA");
}
And finally waitForCompletion:
- (BOOL) waitForCompletion:(NSTimeInterval)timeoutSecs
{
NSDate *timeoutDate = [NSDate dateWithTimeIntervalSinceNow:timeoutSecs];
do {
[[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:timeoutDate];
if([timeoutDate timeIntervalSinceNow] < 0.0)
break;
} while (!done);
return done;
}
Your help is appreciated.
Thanks.

Answer 1

Your issue is that you aren't calling the test method on the object you partially mocked, but are instead alloc'ing a new one in your callMethodAFromTestClassC. If you call it on the proper object, it works fine. See below (note I don't actually create a separate class C, but the effect is the same). As a side note, I think blocks and GCD make life easier, but everyone has their own style.
//
// TestClassTest.m
// TestApp
//
// Created by Benjamin Flynn on 11/20/12.
//
#import <SenTestingKit/SenTestingKit.h>
#import "OCMock.h"
#import "TestClassA.h"
#interface TestClassTest : SenTestCase
#property (nonatomic, retain) TestClassA *testClassA;
#property (atomic, assign) BOOL done;
#end
#implementation TestClassTest
- (void) testCallMethodUsingNSThreadFromADifferentClass
{
self.testClassA = [[TestClassA alloc] init];
id mockTestClassA = [OCMockObject partialMockForObject:self.testClassA];
[[[mockTestClassA expect] andCall:#selector(mockTestMethodA) onObject:self] testMethodA];
[self threadedRequestToCallMethodA];
[self waitForCompletion:5.0];
[mockTestClassA verify];
}
- (void)threadedRequestToCallMethodA
{
[NSThread detachNewThreadSelector:#selector(callMethodAFromTestClassC) toTarget:self withObject:nil];
}
- (void)callMethodAFromTestClassC
{
[self.testClassA testMethodA];
}
- (void)mockTestMethodA
{
NSLog(#"Mock test method A");
self.done = YES;
}
- (BOOL)waitForCompletion:(NSTimeInterval)timeoutSecs
{
NSDate *timeoutDate = [NSDate dateWithTimeIntervalSinceNow:timeoutSecs];
NSLog(#"Starting timer");
do {
[[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:timeoutDate];
if([timeoutDate timeIntervalSinceNow] < 0.0)
break;
} while (!self.done);
NSLog(#"Ending timer");
return self.done;
}
#end