mocking queryset example

example.py

from django.db.models import Count
from .models import DummyModel

class ExampleClass(object):

    def get_queryset(self)

        filter = {
            'foo': 'bar',
            'baz': True
         }

         quertset = DummyModel.objects.filter(**filter).annotate(total=Count('related__field')).values('field', 'total')
         return queryset

test_example.py

from mock import patch
from unittest import TestCase

from example import ExampleClass

class ExampleClassTest(TestCase):

    @patch('example.DummyModel')
    @patch('example.Count')
    def test_get_queryset(self, _count, _dummymodel):

        _count.return_value='counting'
    
        obj = ExampleClass()
        queryset = obj.get_queryset()
    
        _dummymodel.objects.filter.assert_called_once_with(foo='bar', baz=True)
        _dummymodel.objects.filter.return_value.annotate.assert_called_once_with(total='counting')
        _dummy.objects.filter.return_value.annotate.return_value.values.assert_called_once_with('field', 'total')
        
        self.assertEqual(queryset, _dummymodel.objects.filter.return_value.annotate.return_value.values.return_value)