Optimize numeric array conversion and serialize directly into Python bytes

test/test_serialization_identity.py

@@ -0,0 +1,26 @@
+# Copyright (c) 2026 IQ.Lvbs. All rights reserved.
+import hashlib
+import json
+import struct
+from pathlib import Path
+
+import capnp
+import pytest
+
+ROOT = Path(__file__).parent
+CASES = json.loads((ROOT / "serialization-reference.json").read_text())["cases"]
+
+
+@pytest.mark.parametrize("case", CASES, ids=lambda case: str(case["size"]))
+def test_serialization_identity(case):
+    schema = capnp.load(str(ROOT / "all_types.capnp")).TestAllTypes
+    size = case["size"]
+    text_size = case["text_size"]
+    message = schema.new_message(dataField=b"Z" * size, textField="iq" * text_size, float64List=[1.25, -0.0, 123.0])
+    data = message.to_bytes()
+    assert len(data) == case["bytes"]
+    assert struct.unpack_from("<I", data)[0] + 1 == case["segments"]
+    assert hashlib.sha256(data).hexdigest() == case["sha256"]
+    with schema.from_bytes(data) as reader:
+        assert reader.dataField == b"Z" * size
+        assert reader.textField == "iq" * text_size