Python-сообщество

if config.TESTING:
    # Эти функции у нас используются при тестировании
    from datetime import datetime as _datetime, timedelta as _timedelta
    current_time = None

    def now():
        """
        Mock для подмены стандартной функции datetime.now
        """
        global current_time
        if current_time is None:
            current_time = _datetime.now()
        return current_time

    def sleep(seconds):
        """
        Mock для подмены стандартной функции time.sleep
        """
        global current_time
        current_time += _timedelta(seconds=secons)

else:
    # Это используется в реальной работе
    from time import sleep
    from datetime import datetime as _datetime
    now = _datetime.now

import datetime

class A(object):
    now = datetime.datetime.now

    def __init__(self):
        pass

    def f(self):
        return self.now() + datetime.timedelta(minutes=2)

#### Test
import unittest
import mocker

class TestA(unittest.TestCase):
    def setUp(self):
        self.mocker = mocker.Mocker()

    def tearDown(self):
        self.mocker = None

    def test_something(self):
        a = A()
        now = self.mocker.mock()
        a.now = now

        current_time = datetime.datetime(2011, 2, 9, 11, 28, 33)
        expected = datetime.datetime(2011, 2, 9, 11, 30, 33) # 2 mins later
        now()
        self.mocker.result(current_time)

        with self.mocker:
            ret = a.f()
            self.assertEqual(expected, ret)


unittest.main()

        self.assertEqual(billing.can_show(), True)
        time.sleep(4)
        self.assertEqual(billing.can_show(), True)
        time.sleep(4)
        self.assertEqual(billing.can_show(), False)