test_output.py

#!/usr/bin/python
# -*- coding: utf-8 -*-

# python -m unittest test_output

import sys
import unittest

from StringIO import StringIO

def hello():
    print 'hello world'

class OutTest(unittest.TestCase):

    def setUp(self):
        self.output = StringIO()
        self.saved_stdout = sys.stdout
        sys.stdout = self.output

    def tearDown(self):
        self.output.close()
        sys.stdout = self.saved_stdout

    def testOut(self):

        hello()
        self.assertEqual(self.output.getvalue(), 'hello world\n')