[rad_gruchalski]

I did tests for something like this once. Not low level, more of a set of 30+ microservices but the concept is there. The black box testing. This was for a smart home solution based on RabbitMQ. The client wanted to replace RabbitMQ with Kafka but they were anxious because there was no way to verify that the replacement would behave the same way.

So we have spent 2 months writing black box tests against the RabbitMQ version, swapped it out with Kafka and fixed all issues within a couple of weeks.

Since then, I believe that the integration tests are so much more valuable than unit tests.