added DAL serilization test

gluon/tests/test_dal.py

@@ -10,7 +10,7 @@ from fix_path import fix_sys_path
 fix_sys_path(__file__)
 
 
-from gluon.dal import DAL
+from gluon.dal import DAL, Field
 
 
 class TestDALSubclass(unittest.TestCase):
@@ -22,6 +22,15 @@ class TestDALSubclass(unittest.TestCase):
         self.assertEqual(db.representers['rows_render'], sqlhtml.represent)
         self.assertEqual(db.representers['rows_xml'], sqlhtml.SQLTABLE)
 
+    def testSerialization(self):
+        import pickle
+        db = DAL(check_reserved=['all'])
+        db.define_table('t_a', Field('f_a'))
+        db.t_a.insert(f_a='test')
+        a = db(db.t_a.id>0).select(cacheable=True)
+        s = pickle.dumps(a)
+        b = pickle.loads(s)
+        self.assertEqual(a.db, b.db)
 
 """ TODO:
 class TestDefaultValidators(unittest.TestCase):