While looking into the implications of #284 I found that bpython differs in behavior from python when a file test.py contains

from __future__ import division

and I run (b)python -i test.py and then enter 1/2.

I'm not sure how to go about fixing this - if interpreter.runsource (our current technique) doesn't work, I'm not sure what would - maybe we should be ast inspecting test.py for future statements?