Attempt to strengthen gc test

- ensure class registry is empty first
- gc_collect() twice

Change-Id: I61324931bfc1aafce97880320951e568be88f121

diff --git a/test/orm/declarative/test_mixin.py b/test/orm/declarative/test_mixin.py
index eed918572895cedd066a9653d91cdd6f755be8bf..6189014aa9b475f2bb00a3c4ac6975c0847d2fc3 100644 (file)
--- a/test/orm/declarative/test_mixin.py
+++ b/test/orm/declarative/test_mixin.py
@@ -1666,6 +1666,7 @@ class DeclaredAttrTest(DeclarativeTestBase, testing.AssertsCompiledSQL):
     @testing.requires.predictable_gc
     def test_singleton_gc(self):
         counter = mock.Mock()
+        Base.registry._class_registry.clear()
 
         class Mixin(object):
             @declared_attr
@@ -1684,6 +1685,7 @@ class DeclaredAttrTest(DeclarativeTestBase, testing.AssertsCompiledSQL):
         eq_(counter.mock_calls, [mock.call("A")])
         del A
         gc_collect()
+        gc_collect()
 
         from sqlalchemy.orm.clsregistry import _key_is_empty