using fake_ftp in irb

irb only runs the master thread of a script by default. In order to run a FakeFtp::Server instance in a console, you must run irb in --noreadline mode.

$> irb --noreadline
 > s = FakeFtp::Server.new(21212, 21213)
 > s.start

Now you can connect to the server in another irb session.