httpSource = newHttpSource();
// Create sink object, but don't use its toString
// in stream def. Instead, we know it should be named like
// the streamname.
AggregateCounterSink counter = metrics().newAggregateCounterSink(streamName);
stream().create(streamName, "%s | aggregate-counter", httpSource);
httpSource.postData("one");
assertThat(counter, eventually(exists()));
}