The December 2019 release of Apache Kafka 2.4.0 saw usability improvements in TopologyTestDriver, with the addition of new TestInputTopic and TestOutputTopic classes. These offer typesafe methods to easily produce and consume messages for your Kafka Streams tests. In this post we’ll explore these new classes in the context of Avro messages, which requires a small trick to get working.

In a previous post we learned about callouts in Asciidoctor to add explanation to source code. While surfing the Internet I came upon the following blog post by Alex Soto: Auto-numbered Callouts in Asciidoctor. I turns out that since Asciidoctor 1.5.8 we can use a dot (.) instead of explicit numbers to have automatic increasing numbering for the callouts.

Let’s take our example from the earlier blog post and now use auto numbered callouts: