Fixed and restored assertions in OneToOneTests.test_foreign_key.

These assertions had been removed in 34ba8670 and 7fe554b2,
seemingly because they were referencing the wrong objects, and so
they started failing when the checking of object types (as well as
PK values) was introduced.

tests/one_to_one/tests.py

@@ -96,12 +96,15 @@ class OneToOneTests(TestCase):
         assert_filter_waiters(restaurant__place__exact=self.p1.pk)
         assert_filter_waiters(restaurant__place__exact=self.p1)
         assert_filter_waiters(restaurant__place__pk=self.p1.pk)
-        assert_filter_waiters(restaurant__exact=self.p1.pk)
-        assert_filter_waiters(restaurant__pk=self.p1.pk)
-        assert_filter_waiters(restaurant=self.p1.pk)
+        assert_filter_waiters(restaurant__exact=self.r1.pk)
+        assert_filter_waiters(restaurant__exact=self.r1)
+        assert_filter_waiters(restaurant__pk=self.r1.pk)
+        assert_filter_waiters(restaurant=self.r1.pk)
         assert_filter_waiters(restaurant=self.r1)
+        assert_filter_waiters(id__exact=w.pk)
+        assert_filter_waiters(pk=w.pk)
         # Delete the restaurant; the waiter should also be removed
-        r = Restaurant.objects.get(pk=self.p1.pk)
+        r = Restaurant.objects.get(pk=self.r1.pk)
         r.delete()
         self.assertEqual(Waiter.objects.count(), 0)