> It's involved to code a test to cause the partition, wait for the various timeouts to take place, then heal the partition, then wait some more for things to start talking and recovering.

Yet, on the layer that is charged with surviving a partition, that's exactly what you should be doing.

Your unit test can verify that some machine sends the designed message down the wire, it can check if it responds to the expected message, but it can not even check if the software can detect a partition, even less that it can survive one.

I would recommend you make those timeouts configurable from the user point of view.