The system-test module is the place to write aggregate-wide system tests, i.e. system tests that test the functionality of the aggregate as a whole.

The module comes preconfigured with the org.creekservice.system.test Gradle plugin, which adds tasks for running the tests:

./gradlew systemTest

…and configured with the Creek Kafka System Test Extension, which extends the system tests with Kafka topics support. System tests can seed and input records to topics and expect records output to other topics. See the Creek Kafka System Test Extension docs for more info, or the System tests section of the Basic Kafka Streams Tutorial for a quick example.