dpaste.de_snippet.py

my_singleton = None


class Foo(object):

    def __init__(self):
        pass

    def do(arg):
        return arg


def process_foo(foo, arg):
    foo.do(arg)


def do_something():
    # Heavy API call
    raise Exception()
    return 1


def logic():
    # something
    api_response = do_something()
    # something
    return api_response


def print_singleton():
    return my_singleton



######### testfile

from unittest import mock

import demo

from demo import my_singleton

foo_mock = mock.Mock()

demo.process_foo(foo_mock, 4)
foo_mock.do.assert_called_with(4)


@mock.patch('demo.do_something')
def test_logic(m):
    m.return_value = 1
    result = demo.logic()
    m.assert_called_with()
    assert result == 1


test_logic()


demo.my_singleton = 5
my_singleton = 6
assert demo.print_singleton() == 5