GroupBy Test Improvement

ObserveOn was the wrong mechanism for delaying behavior as it was relying on the buffering of observeOn.
Now using delay() to delay the group since observeOn no longer buffers.

Author: benjchristensen

rxjava-core/src/test/java/rx/operators/OperatorGroupByTest.java

@@ -484,21 +484,16 @@ public Integer call(Integer i) {
                     @Override
                     public Observable<Integer> call(GroupedObservable<Integer, Integer> group) {
                         if (group.getKey() == 0) {
-                            return group.observeOn(Schedulers.newThread()).map(new Func1<Integer, Integer>() {
+                            return group.delay(100, TimeUnit.MILLISECONDS).map(new Func1<Integer, Integer>() {
 
                                 @Override
                                 public Integer call(Integer t) {
-                                    try {
-                                        Thread.sleep(2);
-                                    } catch (InterruptedException e) {
-                                        e.printStackTrace();
-                                    }
                                     return t * 10;
                                 }
 
                             });
                         } else {
-                            return group.observeOn(Schedulers.newThread());
+                            return group;
                         }
                     }
                 })