         var outerSubscription: Disposable?
         var inners = Dictionary<String, GroupedObservable<String, String>>()
         var innerSubscriptions = Dictionary<String, Disposable>()
-        var results = Dictionary<String, MockObserver<String>>()
+        var results = Dictionary<String, TestableObserver<String>>()
         
         scheduler.scheduleAt(Defaults.subscribed) {
             let outer: Observable<GroupedObservable<String, String>> = xs.groupBy { x in

                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)

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