I created such an environment for my unit-tests: Wrapping TCP sockets in a stream which only accepts 1 byte at a time in both directions and returns EAGAIN on e

I created such an environment for my unit-tests: Wrapping TCP sockets in a stream which only accepts 1 byte at a time in both directions and returns EAGAIN on every second read provides an easy way to make sure the code on top of the socket does perform all the correct retries. That will most likely not help newcomers which directly write their code agains the OS socket. But once you get a better understanding of the topic and start adding tests to your codebase it's rather easy to add.