Koobs: What thing are you suggesting to mock? The remote server perhaps, which is what I want to do too?

Here is a patch that implements my local SSL server idea by reusing ThreadedEchoServer.

There is one problem with local-server.patch, and I don’t know how to fix it properly. At the end of test_bio_handshake() and test_bio_read_write_data(), the unwrap() call keeps raising SSL_ERROR_SYSCALL and the test hangs in an infinite loop. I could work around this by making the server call unwrap() before shutting the socket down. But it would be better to fix ssl_io_loop() if anyone understands what is going wrong.