kafka 0.10.1 ProcessorTopologyTestDriver issue with .map and .groupByKey.count

[Hamidreza Afzali]

Hi,

When using ProcessorTopologyTestDriver in the latest Kafka 0.10.1, the 
combination of .map(...) and .groupByKey(...).count(...) does not produce any 
result.

The topology looks like this:

builder.stream(Serdes.String, Serdes.Integer, inputTopic)
 .map((k, v) => new KeyValue(fn(k), v))
 .groupByKey(Serdes.String, Serdes.Integer)
 .count(stateStore)

It works if we remove .map(...) or .groupByKey(...).count(...).

Is this a bug?

Thanks in advance,
Hamid