Integration tests with spring-cloud-stream-binder-kafka-streams to prevent duplicate message processing

Question

We are using spring-cloud-stream-binder-kafka-streams:3.1.1 with functional programming. We have set consumer to poll max 5 messages and commit at RECORD level. We want to implement an integration test wherein we stop the consumer followed by a start to check if any of the messages are duplicated to output topic. Any pointers or any sample code will get us going.

Here is our config

spring.cloud.stream.kafka:
  default:
    consumer:
      useNativeEncoding: true
      startOffset: earliest
      max.poll.records: 5
      min.fetch.bytes: 1024000
      fetch.max.wait.ms: 1000
      ackMode: RECORD
      configuration:
        key.serializer: org.apache.kafka.common.serialization.Serdes$StringSerde
        value.serializer: org.apache.kafka.common.serialization.JsonSerde

Thanks,