Initialized using https://github.com/swkBerlin/kata-bootstraps
This setup lets you write the code in Kotlin while it is using Groovy Spock for testing purposes.
Spock is great for data-driven testing, exception tests and mocking! While mixing different languages can be a chore, it might be worth it due to its great feature set.
While the version 1.x supported only Junit4 (or Jupiter Vintage), 2.x comes with full Jupiter support!
Find more info about Spock on its project page.
./gradlew test
Or start them via IntelliJ IDEA which should work with both the Gradle and Junit Runner.