Could you try increasing self.blocking_timeout (in the _setUp function)
to something greater than 0.0 (like 0.1) and see if that works?  I
picked a constant that was as small as Worked For Me to keep the total
test time as short as possible.

Unfortunately select() is called in the guts of Telnet so slipping in a
mock object is difficult.  I could also add more synchronization
primitives but that is also icky.  Hopefully just upping the constant a
little does the trick.