diff --git a/runtests.py b/runtests.py
index c48c18e..0eaea76 100755
--- a/runtests.py
+++ b/runtests.py
@@ -15,6 +15,7 @@ if not settings.configured:
                 'ENGINE': 'django.db.backends.sqlite3',
             }
         },
+        'DEFAULT_AUTO_FIELD': 'django.db.models.AutoField',
         'INSTALLED_APPS': [
             'django.contrib.auth',
             'django.contrib.contenttypes',