[KAFKA-17129] Revisit FindCoordinatorResponse in KafkaConsumerTest

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.9.0
• Component/s: clients, consumer
• Assignee: PoAn Yang
• Reporter: PoAn Yang
• Created: 12/Jul/24 17:25
• Updated: 15/Jul/24 00:18
• Resolved: 15/Jul/24 00:18

Description

Currently, we have many test cases put `client.prepareResponseFrom(FindCoordinatorResponse.prepareResponse(...), ...);` after `newConsumer`. If `FutureResponse` is not in `MockClient`, the request can't get a response. This may cause some flaky tests.
 
In our KafkaConsumerTest design, when starting a `newConsumer` for `AsyncKafkaConsumer`, it always sends `FindCoordinatorRequest`.
 
In `MockClient#send`, if a `FutureResponse` is missing, the request will be add to `requests`. Even if `client.prepareResponseFrom` adds a new `FutureResponse`, it can't be matched to an existent request, so the request can't get a response.
 
It's better to put `client.prepareResponseFrom(FindCoordinatorResponse.prepareResponse(...), ...);` before `newConsumer`, so we don't miss any `FindCoordinatorRequest`.

Issue Links

• links to: GitHub Pull Request #16589