diff --git a/sqlalchemy_utils/decorators.py b/sqlalchemy_utils/decorators.py
index 378053b..decb5eb 100644
--- a/sqlalchemy_utils/decorators.py
+++ b/sqlalchemy_utils/decorators.py
@@ -18,6 +18,9 @@ def generates(attr):
             parts = attr.split('.')
             generator_registry[parts[0]].append(wrapper)
             wrapper.__generates__ = parts[1]
+        elif isinstance(attr, sa.orm.attributes.InstrumentedAttribute):
+            generator_registry[attr.class_.__name__].append(wrapper)
+            wrapper.__generates__ = attr
         else:
             wrapper.__generates__ = attr
         return wrapper
diff --git a/tests/test_generates.py b/tests/test_generates.py
index e41bf5a..9d02427 100644
--- a/tests/test_generates.py
+++ b/tests/test_generates.py
@@ -5,8 +5,8 @@ from tests import TestCase
 
 
 class GeneratesTestCase(TestCase):
-    def setup_method(self, method):
-        TestCase.setup_method(self, method)
+    def teardown_method(self, method):
+        TestCase.teardown_method(self, method)
         decorators.generator_registry = defaultdict(list)
 
     def test_generates_value_before_flush(self):