Build out new declarative systems; deprecate mapper()

The ORM Declarative system is now unified into the ORM itself, with new
import spaces under ``sqlalchemy.orm`` and new kinds of mappings.  Support
for decorator-based mappings without using a base class, support for
classical style-mapper() calls that have access to the declarative class
registry for relationships, and full integration of Declarative with 3rd
party class attribute systems like ``dataclasses`` and ``attrs`` is now
supported.

Fixes: #5508
Change-Id: I130b2b6edff6450bfe8a3e6baa099ff04b5471ff

1 files changed, 6 insertions, 4 deletions

diff --git a/lib/sqlalchemy/testing/entities.py b/lib/sqlalchemy/testing/entities.py
index f5d207bc2..085c19196 100644
--- a/lib/sqlalchemy/testing/entities.py
+++ b/lib/sqlalchemy/testing/entities.py
@@ -39,10 +39,7 @@ class BasicEntity(object):
 _recursion_stack = set()
 
 
-class ComparableEntity(BasicEntity):
-    def __hash__(self):
-        return hash(self.__class__)
-
+class ComparableMixin(object):
     def __ne__(self, other):
         return not self.__eq__(other)
 
@@ -107,3 +104,8 @@ class ComparableEntity(BasicEntity):
             return True
         finally:
             _recursion_stack.remove(id(self))
+
+
+class ComparableEntity(ComparableMixin, BasicEntity):
+    def __hash__(self):
+        return hash(self.__class__)