Fixed #26179 -- Removed null assignment check for non-nullable foreign key fields.

tests/generic_relations/tests.py

@@ -717,14 +717,11 @@ class ProxyRelatedModelTest(TestCase):
 
 
 class TestInitWithNoneArgument(SimpleTestCase):
-    def test_none_not_allowed(self):
-        # TaggedItem requires a content_type, initializing with None should
-        # raise a ValueError.
-        msg = 'Cannot assign None: "TaggedItem.content_type" does not allow null values'
-        with self.assertRaisesMessage(ValueError, msg):
-            TaggedItem(content_object=None)
 
     def test_none_allowed(self):
         # AllowsNullGFK doesn't require a content_type, so None argument should
         # also be allowed.
         AllowsNullGFK(content_object=None)
+        # TaggedItem requires a content_type but initializing with None should
+        # be allowed.
+        TaggedItem(content_object=None)

tests/many_to_one/tests.py

@@ -3,6 +3,7 @@ from copy import deepcopy
 
 from django.core.exceptions import FieldError, MultipleObjectsReturned
 from django.db import models, transaction
+from django.db.utils import IntegrityError
 from django.test import TestCase
 from django.utils import six
 from django.utils.deprecation import RemovedInDjango20Warning
@@ -486,19 +487,19 @@ class ManyToOneTests(TestCase):
         p = Parent.objects.get(name="Parent")
         self.assertIsNone(p.bestchild)
 
-        # Assigning None fails: Child.parent is null=False.
-        with self.assertRaises(ValueError):
-            setattr(c, "parent", None)
+        # Assigning None will not fail: Child.parent is null=False.
+        setattr(c, "parent", None)
 
         # You also can't assign an object of the wrong type here
         with self.assertRaises(ValueError):
             setattr(c, "parent", First(id=1, second=1))
 
-        # Nor can you explicitly assign None to Child.parent during object
-        # creation (regression for #9649).
-        with self.assertRaises(ValueError):
-            Child(name='xyzzy', parent=None)
-        with self.assertRaises(ValueError):
+        # You can assign None to Child.parent during object creation.
+        Child(name='xyzzy', parent=None)
+
+        # But when trying to save a Child with parent=None, the database will
+        # raise IntegrityError.
+        with self.assertRaises(IntegrityError), transaction.atomic():
             Child.objects.create(name='xyzzy', parent=None)
 
         # Creation using keyword argument should cache the related object.

tests/one_to_one/tests.py

@@ -228,9 +228,8 @@ class OneToOneTests(TestCase):
         ug_bar.place = None
         self.assertIsNone(ug_bar.place)
 
-        # Assigning None fails: Place.restaurant is null=False
-        with self.assertRaises(ValueError):
-            setattr(p, 'restaurant', None)
+        # Assigning None will not fail: Place.restaurant is null=False
+        setattr(p, 'restaurant', None)
 
         # You also can't assign an object of the wrong type here
         with self.assertRaises(ValueError):