How come queries aren’t being added to Django’s db.connection.queries in tests?

I’m trying to capture the queries which my code submits to the database by examining the contents of django.db.connection.queries. For some reason though, after all the automatically produced setup queries are logged, no further queries are logged from my own code. The following test case demonstrates the behavior.

from django.test import TestCase
from django.db import reset_queries, connection
from django.contrib.auth.models import User
from django.conf import settings

class Test1(TestCase):
    def setUp(self):
        settings.DEBUG = True

    def test1(self):
        self.assert_(settings.DEBUG, 'DEBUG is False')
        reset_queries() #clears out all the setup queries
        User.objects.all()
        self.assert_(connection.queries, 'No queries')

And here are the results of running it:

Traceback (most recent call last):
  File "/Users/jacob/foo/bar_project/baz_application/tests.py", line 246, in test1
    self.assert_(connection.queries)
AssertionError: No queries

Would anyone be able to shed some light on this? Thanks.

Answer

You will not see any queries after executing User.objects.all(). This is only to be expected. The reason? Querysets are lazy. Unless you do something with the queryset NO query will be triggered. To verify this hypothesis, try the following and see if the test passes.

class Test1(TestCase):
    def setUp(self):
        settings.DEBUG = True

    def test1(self):
        self.assert_(settings.DEBUG, 'DEBUG is False')
        reset_queries() #clears out all the setup queries
        print User.objects.all() # <============= Printing the queryset.
        self.assert_(connection.queries, 'No queries')