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, 11 insertions, 2 deletions

diff --git a/lib/sqlalchemy/testing/fixtures.py b/lib/sqlalchemy/testing/fixtures.py
index 85d3374de..2d3b27917 100644
--- a/lib/sqlalchemy/testing/fixtures.py
+++ b/lib/sqlalchemy/testing/fixtures.py
@@ -15,11 +15,13 @@ from . import schema
 from .engines import drop_all_tables
 from .entities import BasicEntity
 from .entities import ComparableEntity
+from .entities import ComparableMixin  # noqa
 from .util import adict
 from .. import event
 from .. import util
-from ..ext.declarative import declarative_base
-from ..ext.declarative import DeclarativeMeta
+from ..orm import declarative_base
+from ..orm import registry
+from ..orm.decl_api import DeclarativeMeta
 from ..schema import sort_tables_and_constraints
 
 
@@ -383,10 +385,12 @@ class MappedTest(_ORMTest, TablesTest, assertions.AssertsExecutionResults):
     @classmethod
     def _setup_once_mappers(cls):
         if cls.run_setup_mappers == "once":
+            cls.mapper = cls._generate_mapper()
             cls._with_register_classes(cls.setup_mappers)
 
     def _setup_each_mappers(self):
         if self.run_setup_mappers == "each":
+            self.mapper = self._generate_mapper()
             self._with_register_classes(self.setup_mappers)
 
     def _setup_each_classes(self):
@@ -394,6 +398,11 @@ class MappedTest(_ORMTest, TablesTest, assertions.AssertsExecutionResults):
             self._with_register_classes(self.setup_classes)
 
     @classmethod
+    def _generate_mapper(cls):
+        decl = registry()
+        return decl.map_imperatively
+
+    @classmethod
     def _with_register_classes(cls, fn):
         """Run a setup method, framing the operation with a Base class
         that will catch new subclasses to be established within