fix: add docs, tests; tweak some handler method signatures

tests/test_conf.py

@@ -0,0 +1,29 @@
+# -*- coding: utf-8; -*-
+
+from unittest import TestCase
+
+from wuttjamaican.conf import WuttaConfig
+
+from wutta_corepos import conf as mod
+
+
+class TestWuttaCoreposConfigExtension(TestCase):
+
+    def test_configure(self):
+        config = WuttaConfig()
+
+        # no engines by default
+        self.assertFalse(hasattr(config, 'core_office_op_engine'))
+        self.assertFalse(hasattr(config, 'core_office_trans_engine'))
+        self.assertFalse(hasattr(config, 'core_office_arch_engine'))
+        ext = mod.WuttaCoreposConfigExtension()
+        ext.configure(config)
+        self.assertIsNone(config.core_office_op_engine)
+        self.assertIsNone(config.core_office_trans_engine)
+        self.assertIsNone(config.core_office_arch_engine)
+
+        # but config can change that
+        config.setdefault('corepos.db.office_op.default.url', 'sqlite://')
+        ext.configure(config)
+        self.assertIsNotNone(config.core_office_op_engine)
+        self.assertEqual(str(config.core_office_op_engine.url), 'sqlite://')