✅(backend) override defaults.NB_OBJECTS for the demo tests

Otherwise when you increase the number of objects to test how the
application scales, the demo test will take too long...

src/backend/demo/tests/test_commands_create_demo.py

@@ -1,4 +1,5 @@
 """Test the `create_demo` management command"""
+from unittest import mock
 
 from django.core.management import call_command
 from django.test import override_settings
@@ -10,15 +11,20 @@ from core import models
 pytestmark = pytest.mark.django_db
 
 
+@mock.patch("demo.defaults.NB_OBJECTS", {
+        "users": 10,
+        "docs": 10,
+        "max_users_per_document": 5,
+    }  )
 @override_settings(DEBUG=True)
 def test_commands_create_demo():
     """The create_demo management command should create objects as expected."""
     call_command("create_demo")
 
     assert models.Template.objects.count() == 1
-    assert models.User.objects.count() >= 50
-    assert models.Document.objects.count() >= 50
-    assert models.DocumentAccess.objects.count() > 50
+    assert models.User.objects.count() >= 10
+    assert models.Document.objects.count() >= 10
+    assert models.DocumentAccess.objects.count() > 10
 
     # assert dev users have doc accesses
     user = models.User.objects.get(email="impress@impress.world")