[soc2009/multidb] Correctly handle pickling of Query objects, restoring them to the correct database.

git-svn-id: http://code.djangoproject.com/svn/django/branches/soc2009/multidb@11274 bcc190cf-cafb-0310-a4f2-bffc1f526a37

tests/regressiontests/multiple_database/tests.py

@@ -1,4 +1,5 @@
 import datetime
+import pickle
 
 from django.conf import settings
 from django.db import connections
@@ -79,6 +80,15 @@ class QueryTestCase(TestCase):
             months = Book.objects.dates('published', 'month').using(db)
             self.assertEqual(sorted(o.month for o in months), [5, 12])
 
+class PickleQuerySetTestCase(TestCase):
+    def test_pickling(self):
+        for db in connections:
+            qs = Book.objects.all()
+            self.assertEqual(qs.query.connection,
+                pickle.loads(pickle.dumps(qs)).query.connection)
+            self.assertEqual(qs._using, pickle.loads(pickle.dumps(qs))._using)
+
+
 if len(settings.DATABASES) > 1:
     class MetaUsingTestCase(TestCase):
         def test_meta_using_queries(self):