A library for mocking django queryset functions in memory for testing
Latest commit 2f2b577 Feb 17, 2017 @stphivos committed on GitHub Merge pull request #34 from cfe-lab/quirky-queries
Add some quirky queries supported by Django: pk is in a subquery and child is equal.


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Django Mock Queries

A library for mocking Django queryset functions in memory for testing


  • QuerySet style support for method chaining
  • Filtering with Q objects
  • Aggregates generation
  • CRUD functions
  • Field lookups
  • django-rest-framework serializer asserts


from django.db.models import Avg, Q
from django_mock_queries.query import MockSet, MockModel

qs = MockSet(
    MockModel(mock_name='john', email='john@gmail.com'),
    MockModel(mock_name='jeff', email='jeff@hotmail.com'),
    MockModel(mock_name='bill', email='bill@gmail.com'),

print [x for x in qs.all().filter(email__icontains='gmail.com').select_related('address')]
# Outputs: [john, bill]

qs = MockSet(
    MockModel(mock_name='model s', msrp=70000),
    MockModel(mock_name='model x', msrp=80000),
    MockModel(mock_name='model 3', msrp=35000),

print qs.all().aggregate(Avg('msrp'))
# Outputs: {'msrp__avg': 61666}

qs = MockSet(
    MockModel(mock_name='model x', make='tesla', country='usa'),
    MockModel(mock_name='s-class', make='mercedes', country='germany'),
    MockModel(mock_name='s90', make='volvo', country='sweden'),

print [x for x in qs.all().filter(Q(make__iexact='tesla') | Q(country__iexact='germany'))]
# Outputs: [model x, s-class]

qs = MockSet(cls=MockModel)
print qs.create(mock_name='my_object', foo='1', bar='a')
# Outputs: my_object

print [x for x in qs]
# Outputs: [my_object]

Test function that uses Django QuerySet:

Function that queries active users
def active_users(self):
    return User.objects.filter(is_active=True).all()

Test function applies expected filters by patching Django's user model Manager or Queryset with a MockSet
from django_mock_queries.query import MockSet, MockModel

class TestApi(TestCase):
    users = MockSet()
    user_objects = patch('django.contrib.auth.models.User.objects', users)

    def test_api_active_users_filters_by_is_active_true(self):
            MockModel(mock_name='active user', is_active=True),
            MockModel(mock_name='inactive user', is_active=False)

        for x in self.api.active_users():
            assert x.is_active

Test django-rest-framework model serializer:

Car model serializer that includes a nested serializer and a method field
class CarSerializer(serializers.ModelSerializer):
    make = ManufacturerSerializer()
    speed = serializers.SerializerMethodField()

    def get_speed(self, obj):
        return obj.format_speed()

    class Meta:
        model = Car
        fields = ('id', 'make', 'model', 'speed',)

Test serializer returns fields with expected values and mock the result of nested serializer for field make
def test_car_serializer_fields(self):
    car = Car(id=1, make=Manufacturer(id=1, name='vw'), model='golf', speed=300)

    values = {
        'id': car.id,
        'model': car.model,
        'speed': car.formatted_speed(),

    assert_serializer(CarSerializer) \
        .instance(car) \
        .returns('id', 'make', 'model', 'speed') \
        .values(**values) \
        .mocks('make') \

Full Example

There is a full Django application in the examples/users folder. It shows how to configure django_mock_queries in your tests and run them with or without setting up a Django database. Running the mock tests without a database can be much faster when your Django application has a lot of database migrations.

To run your Django tests without a database, add a new settings file, and call monkey_patch_test_db(). Use a wildcard import to get all the regular settings as well.

# settings_mocked.py
from django_mock_queries.mocks import monkey_patch_test_db

from users.settings import *


Then run your Django tests with the new settings file:

./manage.py test --settings=users.settings_mocked

Here's the pytest equivalent:

pytest --ds=users.settings_mocked

That will run your tests without setting up a test database. All of your tests that use Django mock queries should run fine, but what about the tests that really need a database?

ERROR: test_create (examples.users.analytics.tests.TestApi)
Traceback (most recent call last):
  File "/.../examples/users/analytics/tests.py", line 28, in test_create
    start_count = User.objects.count()
NotSupportedError: Mock database tried to execute SQL for User model.

If you want to run your tests without a database, you need to tell Django to skip the tests that need a database. You can do that by putting a skip decorator on the test classes or test methods that need a database.

class TestApi(TestCase):
    def test_create(self):
        start_count = User.objects.count()

        final_count = User.objects.count()

        self.assertEqual(start_count + 1, final_count)


$ pip install django_mock_queries


Anything missing or not functioning correctly? PRs are always welcome! Otherwise, you can create an issue so someone else does it when time allows.

You can follow these guidelines:

  • Fork the repo from this page
  • Clone your fork:
$ git clone https://github.com/{your-username}/django-mock-queries.git
$ cd django-mock-queries
$ git checkout -b feature/your_cool_feature
  • Implement feature/fix
  • Add/modify relevant tests
  • Run tox to verify all tests and flake8 quality checks pass
$ tox
  • Commit and push local branch to your origin
$ git commit . -m "New cool feature does this"
$ git push -u origin HEAD
  • Create pull request


  • Add support for missing queryset functions and field lookups
  • Implement decorators for unified model patching