Find a way to make the tests more portable

[watzon]

Currently the spec tries to authenticate with a pubkey on port 2222 which naturally will fail on most systems. The only way I can think of to circumvent this and make the tests more portable would either be to provide a user (probably with the shell set to /dev/null) on an existing server and allow them ssh login, or run a local ssh server on a random port in Crystal.

[alexanderadam]

I like this idea. It would be nice to spawn a server with crystal_ssh for that.