             error(570, testError)
             ])
         
-        let results: MockObserver<String> = scheduler.createObserver(String)
+        let results: TestableObserver<String> = scheduler.createObserver(String)
         var outerSubscription: Disposable?
         var inner: GroupedObservable<String, String>?
         var innerSubscription: Disposable?

                return x.lowercaseString.trimWhitespace()
            }
            outerSubscription = outer.subscribeNext({ (group: GroupedObservable<String, String>) -> Void in
                let result: MockObserver<String> = scheduler.createObserver(String)
                inners[group.key] = group
                results[group.key] = result
                innerSubscriptions[group.key] = group.subscribe(result)

        
        scheduler.scheduleAt(Defaults.subscribed) {
            outerSubscription = outer!.subscribeNext { (group: GroupedObservable<String, String>) -> Void in
                let result: TestableObserver<String> = scheduler.createObserver(String)
                inners[group.key] = group
                results[group.key] = result
                
