[AdrenalinMd]

It's not really a middle ground if you're not testing your service in the same conditions as in production environment.

If you're not testing integration with Kafka, and the producer, your service is still lacking integration tests.

Testing classes in isolation with testcontainer is fine. But I observed that with microservice architecture the line between E2E tests and integration tests are blurred.

Microservices can and should be tested from the client perspective.

[TeeWEE]

True but if you want to test every merge-request it becomes expensive.

We had a customer k8s cluster per feature branch with e2e testing.

A middle ground is testcontainers for feature branches, and the trunk branch a full e2e suite deployed to a live cluster...