External Patching

#
# my_package.my_module
#

from time import sleep


def my_sleep(duration_secs):
    print('Sleeping for {n} seconds'.format(n=duration_secs))
    sleep(duration_secs)


#
# my_package.test.test_my_module
#

import simian
from my_package import my_module


@simian.patch(my_module, external=['time.sleep'])
def test_my_sleep(master_mock):
    my_module.my_sleep(99)
    master_mock.sleep.assert_called_once_with(99)

Internal Patching

The above example demonstrates external patching, but internal (same-module) patching works as well. Let’s extend the above example.

#
# my_package.my_module
#

from time import sleep


def my_sleep(duration_secs):
    my_logger('Starting {n}-second sleep'.format(n=duration_secs))
    sleep(duration_secs)
    my_logger('Finished {n}-second sleep'.format(n=duration_secs))


def my_logger(msg):
    print(msg)


#
# my_package.test.test_my_module
#

import simian
from mock import call
from my_package import my_module


@simian.patch(my_module, external=['time.sleep'], internal=['my_logger'])
def test_my_sleep(master_mock):
    my_module.my_sleep(99)
    master_mock.assert_has_calls(
        calls=[
            call.my_logger('Starting 99-second sleep'),
            call.sleep(99),
            call.my_logger('Finished 99-second sleep')],
        any_order=False)