How to clear topics in tests with Spring Kafka

Question

I'm writing a unit test with Spring Kafka 2.4 to prove that my Spring Boot setup is correct. I'm validating that SeekToCurrentBatchErrorHandler works as expected which requires sending an incorrect message that should be retried. Unfortunately this incorrect messages breaks other tests because this message will be retried forever.

Because of above I'd like to ensure that each test is correctly isolated. I either need to:

1. Delete and recreate the Kafka topic with AdminClient

2. Seek to the end of the existing Kafka topic and commit new offsets

I was trying option 2 with Consumer.seekToEnd() method however Spring Kafka hides the created consumers behind few layers of internal framework classes. I'm also not 100% sure if this method can be called in test thread which is different from listener thread.

What is the recommended way to clear topics in tests with Spring Kafka?

Answer 1

Best practice is to use unique topic names in each test to provide complete isolation; you could also stop the container(s), create a new Consumer with the same group.id and perform the seeks there.