Hello, maybe anyone already have implemented ingestion for Kafka Connect S3 sink ?

Hi @cuddly-refrigerator-2629! We don’t yet support this lineage edge, but this would be a great contribution to the project! teamwork

I have already started the implementation, but don't see any tests for the existing connectors ( Debezium and Jdbc). Is it possible to contribute without test cases for the S3 Sink connector ?

Yes, you can contribute without test cases - please see our contributing guidelines here!