iOS Unit testing - bad access error when using NSRunLoop and AFNetworking at the same time

Question

I'm using the code below to test asynchronous calls using AFNetworking in my unit tests for iOS7. When I run the test alone, or even the entire test case, the code works fine. However, when I run the entire test suite, I get EXC_BAD_ACCESS (code=1, address0x7a) on the line [theRL runMode:NSDefaultRunLoopMode beforeDate:date];

  NSRunLoop *theRL = [NSRunLoop currentRunLoop];

    //setup timeout
    float waitIncrement = 0.1f;
    int timeoutCounter  = (int)(60 / waitIncrement); //30 sec timeout
    BOOL controlConditionReached = NO;


    // Begin a run loop terminated when the downloadComplete it set to true
    while (controlConditionReached == NO)
    {
        NSDate* date = [NSDate dateWithTimeIntervalSinceNow:waitIncrement];

        //Here: EXC_BAD_ACCESS (code=1, address0x7a) when running the entire test suite
        [theRL runMode:NSDefaultRunLoopMode beforeDate:date];
        //control condition is set in one of your async operation delegate methods or blocks
        controlConditionReached = self.downloadComplete || self.downloadFailed||self.cachedVideoAvailable ;

        //if there's no response - timeout after some time
        if(--timeoutCounter <= 0)
        {
            break;
        }
    }

I see that at the same time as I'm using my loop, AFNetoworking is using this method:

+ (void)networkRequestThreadEntryPoint:(id)__unused object {
    @autoreleasepool {
        [[NSThread currentThread] setName:@"AFNetworking"];

        NSRunLoop *runLoop = [NSRunLoop currentRunLoop];
        [runLoop addPort:[NSMachPort port] forMode:NSDefaultRunLoopMode];
        [runLoop run];
    }
}

How can I identify what is causing this error? If I change my method's run loop mode to NSRunLoopCommonModes, then all of my tests fail