Sample code illustrating some uses of Mock; These tests will pass if you have nose, but the code doesn't really do anything.

examples.py

import requests
from pygithub3 import Github


# Example: Hit a 3rd-party API
# ----------------------------

def get_user(username):
    gh = Github()
    return gh.users.get(username)


# Example: Side Effects
# ---------------------

def fetch():
    """Asumme you're hitting some API."""
    try:
        response = requests.get('http://example.com')
        return response.content
    except requests.HTTPError:
        return None


# Example: "expensive" calls
# --------------------------

class User(object):

    def activities(self):
        """does expensive DB queries"""
        # ...
        return ''

    def dashboard(self):
        """groups user activities"""

        results = []
        for activity in self.activities():
            # do some stuff
            results.append(activity)

        return results


# Example: Lots of Setup
# ----------------------

def list_user_activities(username):

    # Assume there's an ORM attached to User
    u = User.objects.get(username=username)

    # Assume the ``activities`` method returns an iterable of
    # Activity objects that have a ``title`` attribute.
    return [a.title for a in u.activities()]

test_examples.py

from mock import call, patch, Mock
from examples import fetch, get_user, list_user_activities, User


# Example: Hit a 3rd-party API
# ----------------------------

def test_get_user():
    with patch('examples.Github') as mock_github:

        mock_gh = mock_github.return_value

        get_user('foo')  # call our function
        mock_github.assert_has_calls([
            call()
        ])

        mock_gh.assert_has_calls([
            call.users.get('foo')
        ])


# Example: Side Effects
# ---------------------

def test_fetch():
    config = {
        'get.side_effect':  Exception,
        'HTTPError': Exception,
    }
    with patch('examples.requests', **config) as mock_requests:
        result = fetch()
        assert result is None

        mock_requests.assert_has_calls([
            call.get('http://example.com')
        ])


# Example: "expensive" calls
# --------------------------

def test_user_dashboard():

    u = User()
    u.activities = Mock(return_value=['blah'])

    result = u.dashboard()
    assert result == ['blah']
    assert u.activities.called


# Example: Lots of Setup
# ----------------------

def test_list_user_activities():

    # Mock an activity object; If you attempt to access an attribute that's
    # not in the spec, this Mock will raise an AttributeError.
    mock_activity = Mock(spec=['title'])

    # Mock User instance; provide a return value for the ``activities`` method
    config = {'activities.return_value': [mock_activity]}
    mock_user_instance = Mock(**config)

    # Mock User Class (via patch)
    config = {'objects.get.return_value': mock_user_instance}
    with patch('examples.User', **config) as mock_user_class:

        list_user_activities('xavier')
        mock_user_class.assert_has_calls([
            call.objects.get(username='xavier')
        ])

        mock_user_instance.assert_has_calls([
            call.activities()
        ])