Adventures in Nose: nosetests and unbuffered stdout.

In some of our server code, we like to insure we get unbuffered output, like in perl.  In Python, this is easy to do:

import sys

sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0)

However, using the wonderful nosetest for testing will barf on this code, because it reassigns stdout to a cStringIO for capturing.

This is a workaround:

import sys
import os

try:   # get unbuffered output
    sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0)
except AttributeError, exc: # under nose, sys.stdout is reassigned to a string buffer
    pass

def test():
    assert 1

Alternately, run nosetests -s, which disables the output capture feature.

Cf:  my embarrassing bug report over at nose