Hey, all, maybe we can jump-start this discussion. I think this approach would be very ergonomic for testing, and would help reduce boilerplate in tests.
The think I like most about it is that it mirrors the mental model that people already have from Kafka Streams, in which you write to an "input topic" and then get your results from an "output topic". As a side benefit, the input and output topics in the proposal also close over the serdes, which makes it much less boilerplate for test code. If I can offer one suggestion for change, I'm not sure I'm totally sold on the need for a new abstraction "ClientRecord" with an implementation for tests "TestRecord". It seems like this unnecessarily complicates the main (non-testing) data model. It seems like it would be sufficient, and just as ergonomic, to have the input topic accept ProducerRecords and the output topic return ConsumerRecords. I'm open to discussion on this point, though. Thanks for the proposal, Jukka! -John On Mon, May 20, 2019 at 7:59 AM Jukka Karvanen <jukka.karva...@jukinimi.com> wrote: > > Hi All, > > I would like to start the discussion on KIP-470: TopologyTestDriver test > input and output usability improvements: > https://cwiki.apache.org/confluence/display/KAFKA/KIP-470%3A+TopologyTestDriver+test+input+and+output+usability+improvements > > > This KIP is inspired by the Discussion in KIP-456: Helper classes to make > it simpler to write test logic with TopologyTestDriver: > https://cwiki.apache.org/confluence/display/KAFKA/KIP-456 > %3A+Helper+classes+to+make+it+simpler+to+write+test+logic+with+TopologyTestDriver > > > The proposal in KIP-456 > <https://cwiki.apache.org/confluence/display/KAFKA/KIP-456%3A+Helper+classes+to+make+it+simpler+to+write+test+logic+with+TopologyTestDriver> > was > to add alternate way to input and output topic, but this KIP enhance those > classes and deprecate old functionality to make clear interface for test > writer to use. > > In current KIP-470 proposal, topic objects are created with topicName and > related serders. > public final <K, V> TestInputTopic<K, V> createInputTopic(final String > topicName, final Serde<K> keySerde, final Serde<V> valueSerde); > public final <K, V> TestOutputTopic<K, V> createOutputTopic(final String > topicName, final Serde<K> keySerde, final Serde<V> valueSerde); > One thing I wondered if there way to find out topic related serde from > TopologyTestDriver topology, it would simply creation of these Topic > objects: > public final <K, V> TestInputTopic<K, V> createInputTopic(final String > topicName); > public final <K, V> TestOutputTopic<K, V> createOutputTopic(final String > topicName); > > KIP-456 can be discarded if this KIP get accepted. > > > Best Regards, > Jukka
