diff --git a/tests/many_to_one/tests.py b/tests/many_to_one/tests.py
index 7538f238f2..a5215e58d7 100644
--- a/tests/many_to_one/tests.py
+++ b/tests/many_to_one/tests.py
@@ -152,6 +152,22 @@ class ManyToOneTests(TestCase):
         self.assertFalse(hasattr(self.r2.article_set, 'remove'))
         self.assertFalse(hasattr(self.r2.article_set, 'clear'))
 
+    def test_assign_fk_id_value(self):
+        parent = Parent.objects.create(name='jeff')
+        child1 = Child.objects.create(name='frank', parent=parent)
+        child2 = Child.objects.create(name='randy', parent=parent)
+        parent.bestchild = child1
+        parent.save()
+        parent.bestchild_id = child2.pk
+        parent.save()
+        self.assertEqual(parent.bestchild_id, child2.pk)
+        self.assertFalse(Parent.bestchild.is_cached(parent))
+        self.assertEqual(parent.bestchild, child2)
+        self.assertTrue(Parent.bestchild.is_cached(parent))
+        # Reassigning the same value doesn't clear cached instance.
+        parent.bestchild_id = child2.pk
+        self.assertTrue(Parent.bestchild.is_cached(parent))
+
     def test_selects(self):
         self.r.article_set.create(headline="John's second story", pub_date=datetime.date(2005, 7, 29))
         self.r2.article_set.create(headline="Paul's story", pub_date=datetime.date(2006, 1, 17))
diff --git a/tests/one_to_one/tests.py b/tests/one_to_one/tests.py
index 51e358c7f9..78b3ff1135 100644
--- a/tests/one_to_one/tests.py
+++ b/tests/one_to_one/tests.py
@@ -205,6 +205,18 @@ class OneToOneTests(TestCase):
         # reverse cache has a value of None.
         p.undergroundbar = None
 
+    def test_assign_o2o_id_value(self):
+        b = UndergroundBar.objects.create(place=self.p1)
+        b.place_id = self.p2.pk
+        b.save()
+        self.assertEqual(b.place_id, self.p2.pk)
+        self.assertFalse(UndergroundBar.place.is_cached(b))
+        self.assertEqual(b.place, self.p2)
+        self.assertTrue(UndergroundBar.place.is_cached(b))
+        # Reassigning the same value doesn't clear a cached instance.
+        b.place_id = self.p2.pk
+        self.assertTrue(UndergroundBar.place.is_cached(b))
+
     def test_related_object_cache(self):
         """ Regression test for #6886 (the related-object cache) """