1 files changed, 15 insertions, 0 deletions
diff --git a/tests/model_forms/tests.py b/tests/model_forms/tests.py
index f3317f59de..b14e0e2389 100644
--- a/tests/model_forms/tests.py
+++ b/tests/model_forms/tests.py
@@ -3142,3 +3142,18 @@ class StrictAssignmentTests(TestCase):
             '__all__': ['Cannot set attribute'],
             'title': ['This field cannot be blank.']
         })
+
+
+class ModelToDictTests(TestCase):
+    def test_many_to_many(self):
+        """Data for a ManyToManyField is a list rather than a lazy QuerySet."""
+        blue = Colour.objects.create(name='blue')
+        red = Colour.objects.create(name='red')
+        item = ColourfulItem.objects.create()
+        item.colours.set([blue])
+        data = model_to_dict(item)['colours']
+        self.assertEqual(data, [blue])
+        item.colours.set([red])
+        # If data were a QuerySet, it would be reevaluated here and give "red"
+        # instead of the original value.
+        self.assertEqual(data, [blue])