fix: add util module, w/ model_transaction_query()

just a basic implementation, will have to improve later

src/wutta_continuum/testing.py

@@ -0,0 +1,92 @@
+# -*- coding: utf-8; -*-
+################################################################################
+#
+#  Wutta-Continuum -- SQLAlchemy Versioning for Wutta Framework
+#  Copyright © 2024-2025 Lance Edgar
+#
+#  This file is part of Wutta Framework.
+#
+#  Wutta Framework is free software: you can redistribute it and/or modify it
+#  under the terms of the GNU General Public License as published by the Free
+#  Software Foundation, either version 3 of the License, or (at your option) any
+#  later version.
+#
+#  Wutta Framework is distributed in the hope that it will be useful, but
+#  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+#  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+#  more details.
+#
+#  You should have received a copy of the GNU General Public License along with
+#  Wutta Framework.  If not, see <http://www.gnu.org/licenses/>.
+#
+################################################################################
+"""
+Testing utilities
+"""
+
+import sys
+
+import sqlalchemy_continuum as continuum
+
+from wuttjamaican.testing import DataTestCase
+
+from wutta_continuum.conf import WuttaContinuumConfigExtension
+
+
+class VersionTestCase(DataTestCase):
+    """
+    Base class for test suites requiring the SQLAlchemy-Continuum
+    versioning feature.
+
+    This inherits from
+    :class:`~wuttjamaican:wuttjamaican.testing.DataTestCase`.
+    """
+
+    def setUp(self):
+        self.setup_versioning()
+
+    def setup_versioning(self):
+        """
+        Do setup tasks relating to this class, as well as its parent(s):
+
+        * call :meth:`wuttjamaican:wuttjamaican.testing.DataTestCase.setup_db()`
+
+          * this will in turn call :meth:`make_config()`
+        """
+        self.setup_db()
+
+    def tearDown(self):
+        self.teardown_versioning()
+
+    def teardown_versioning(self):
+        """
+        Do teardown tasks relating to this class, as well as its parent(s):
+
+        * call :func:`sqlalchemy-continuum:sqlalchemy_continuum.remove_versioning()`
+        * call :meth:`wuttjamaican:wuttjamaican.testing.DataTestCase.teardown_db()`
+        """
+        continuum.remove_versioning()
+        continuum.versioning_manager.transaction_cls = continuum.TransactionFactory()
+        self.teardown_db()
+
+    def make_config(self, **kwargs):
+        """
+        Make and customize the config object.
+
+        We override this to explicitly enable the versioning feature.
+        """
+        config = super().make_config(**kwargs)
+        config.setdefault("wutta_continuum.enable_versioning", "true")
+
+        # nb. must purge model classes from sys.modules, so they will
+        # be reloaded and sqlalchemy-continuum can reconfigure
+        if "wuttjamaican.db.model" in sys.modules:
+            del sys.modules["wuttjamaican.db.model.batch"]
+            del sys.modules["wuttjamaican.db.model.upgrades"]
+            del sys.modules["wuttjamaican.db.model.auth"]
+            del sys.modules["wuttjamaican.db.model.base"]
+            del sys.modules["wuttjamaican.db.model"]
+
+        ext = WuttaContinuumConfigExtension()
+        ext.startup(config)
+        return config