capturing both stderr and std to a single list of strings.

capture_all.py

from cStringIO import StringIO
class Capturing(list):
    def __enter__(self):
        self._stdout = sys.stdout
        self._stderr = sys.stderr

        sys.stdout = self._stringio = StringIO()
        sys.stderr = self._stringio

        return self
    def __exit__(self, *args):
        self.extend(self._stringio.getvalue().splitlines())
        del self._stringio    # free up some memory
        sys.stdout = self._stdout
        sys.stderr = self._stderr

# creates a list
with Capturing() as output:
    print "foo" #can also send to stderr