feat: add the import-versions command, handler logic

only works if wutta-continuum is already installed and enabled.

this also rearranges some existing classes, for better consistency

tests/importing/test_handlers.py

@@ -213,6 +213,97 @@ class TestFromFileHandler(DataTestCase):
             process_data.assert_called_once_with(input_file_dir=self.tempdir)
 
 
+class TestFromSqlalchemyHandler(DataTestCase):
+
+    def make_handler(self, **kwargs):
+        return mod.FromSqlalchemyHandler(self.config, **kwargs)
+
+    def test_make_source_session(self):
+        handler = self.make_handler()
+        self.assertRaises(NotImplementedError, handler.make_source_session)
+
+    def test_begin_source_transaction(self):
+        handler = self.make_handler()
+        self.assertIsNone(handler.source_session)
+        with patch.object(handler, "make_source_session", return_value=self.session):
+            handler.begin_source_transaction()
+        self.assertIs(handler.source_session, self.session)
+
+    def test_commit_source_transaction(self):
+        model = self.app.model
+        handler = self.make_handler()
+        handler.source_session = self.session
+        self.assertEqual(self.session.query(model.User).count(), 0)
+
+        # nb. do not commit this yet
+        user = model.User(username="fred")
+        self.session.add(user)
+
+        self.assertTrue(self.session.in_transaction())
+        self.assertIn(user, self.session)
+        handler.commit_source_transaction()
+        self.assertIsNone(handler.source_session)
+        self.assertFalse(self.session.in_transaction())
+        self.assertNotIn(user, self.session)  # hm, surprising?
+        self.assertEqual(self.session.query(model.User).count(), 1)
+
+    def test_rollback_source_transaction(self):
+        model = self.app.model
+        handler = self.make_handler()
+        handler.source_session = self.session
+        self.assertEqual(self.session.query(model.User).count(), 0)
+
+        # nb. do not commit this yet
+        user = model.User(username="fred")
+        self.session.add(user)
+
+        self.assertTrue(self.session.in_transaction())
+        self.assertIn(user, self.session)
+        handler.rollback_source_transaction()
+        self.assertIsNone(handler.source_session)
+        self.assertFalse(self.session.in_transaction())
+        self.assertNotIn(user, self.session)
+        self.assertEqual(self.session.query(model.User).count(), 0)
+
+    def test_get_importer_kwargs(self):
+        handler = self.make_handler()
+        handler.source_session = self.session
+        kw = handler.get_importer_kwargs("User")
+        self.assertIn("source_session", kw)
+        self.assertIs(kw["source_session"], self.session)
+
+
+class TestFromWuttaHandler(DataTestCase):
+
+    def make_handler(self, **kwargs):
+        return mod.FromWuttaHandler(self.config, **kwargs)
+
+    def test_get_source_title(self):
+        handler = self.make_handler()
+
+        # uses app title by default
+        self.config.setdefault("wutta.app_title", "What About This")
+        self.assertEqual(handler.get_source_title(), "What About This")
+
+        # or generic default if present
+        handler.generic_source_title = "WHATABOUTTHIS"
+        self.assertEqual(handler.get_source_title(), "WHATABOUTTHIS")
+
+        # but prefer specific title if present
+        handler.source_title = "what_about_this"
+        self.assertEqual(handler.get_source_title(), "what_about_this")
+
+    def test_make_source_session(self):
+        handler = self.make_handler()
+
+        # makes "new" (mocked in our case) app session
+        with patch.object(self.app, "make_session") as make_session:
+            make_session.return_value = self.session
+            session = handler.make_source_session()
+            make_session.assert_called_once_with()
+            self.assertIs(session, self.session)
+
+
 class TestToSqlalchemyHandler(DataTestCase):
 
     def make_handler(self, **kwargs):
@@ -256,3 +347,34 @@ class TestToSqlalchemyHandler(DataTestCase):
         kw = handler.get_importer_kwargs("Setting")
         self.assertIn("target_session", kw)
         self.assertIs(kw["target_session"], self.session)
+
+
+class TestToWuttaHandler(DataTestCase):
+
+    def make_handler(self, **kwargs):
+        return mod.ToWuttaHandler(self.config, **kwargs)
+
+    def test_get_target_title(self):
+        handler = self.make_handler()
+
+        # uses app title by default
+        self.config.setdefault("wutta.app_title", "What About This")
+        self.assertEqual(handler.get_target_title(), "What About This")
+
+        # or generic default if present
+        handler.generic_target_title = "WHATABOUTTHIS"
+        self.assertEqual(handler.get_target_title(), "WHATABOUTTHIS")
+
+        # but prefer specific title if present
+        handler.target_title = "what_about_this"
+        self.assertEqual(handler.get_target_title(), "what_about_this")
+
+    def test_make_target_session(self):
+        handler = self.make_handler()
+
+        # makes "new" (mocked in our case) app session
+        with patch.object(self.app, "make_session") as make_session:
+            make_session.return_value = self.session
+            session = handler.make_target_session()
+            make_session.assert_called_once_with()
+            self.assertIs(session, self.session)