DEKAF
This is a Kafka emulator that has just enough functionality to serve as a data provider to a handful of systems. It may not be compatible with all Kafka clients. The API version it supports is roughly equivalent to Kakfa 0.10.
It is heavily based on this repo: https://github.com/travisjeffery/jocko
It is designed to be used as a library and there are several examples.
See Examples here.