feat: add archive client foundation

tests/test_state.py

@@ -0,0 +1,28 @@
+import tempfile
+import unittest
+from pathlib import Path
+from uuid import uuid4
+
+from archive_clients.state import ClientStore, CommandConflict
+
+
+class ClientStoreTests(unittest.TestCase):
+    def test_command_acceptance_is_durable_and_content_addressed(self):
+        with tempfile.TemporaryDirectory() as directory:
+            database = Path(directory) / "state.db"
+            store = ClientStore(database)
+            store.initialize()
+            command_id = str(uuid4())
+            first = store.accept_command(command_id, '{"b":2,"a":1}', '{"ok":true}')
+            duplicate = ClientStore(database).accept_command(
+                command_id, '{"a":1,"b":2}', '{"ok":false}'
+            )
+            self.assertFalse(first.duplicate)
+            self.assertTrue(duplicate.duplicate)
+            self.assertEqual(duplicate.acknowledgement_json, '{"ok":true}')
+            with self.assertRaises(CommandConflict):
+                store.accept_command(command_id, '{"a":2}', '{"ok":true}')
+
+
+if __name__ == "__main__":
+    unittest.main()