From 0b8a21e6aa4fe4ae8a66164faa7b0199cda1737e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?L=27=C3=A9lectron=20rare?=
 <108685187+electron-rare@users.noreply.github.com>
Date: Wed, 13 May 2026 13:27:51 +0200
Subject: [PATCH] test(smplx-tcp): serialize round-trip + offsets

---
 .../tests/test_smplx_osc_sender_serialize.py  | 69 +++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 data_only_viz/tests/test_smplx_osc_sender_serialize.py

diff --git a/data_only_viz/tests/test_smplx_osc_sender_serialize.py b/data_only_viz/tests/test_smplx_osc_sender_serialize.py
new file mode 100644
index 0000000..2b75493
--- /dev/null
+++ b/data_only_viz/tests/test_smplx_osc_sender_serialize.py
@@ -0,0 +1,69 @@
+"""SMPLXTCPSender._serialize_persons produces the expected binary frame."""
+
+import struct
+import numpy as np
+
+from data_only_viz.smplx_osc_sender import SMPLXTCPSender
+from data_only_viz.state import SMPLXPerson
+
+# Frame header: MAGIC(4) + n_persons(4) = 8 bytes before per-person data
+_HEADER = 8
+# Per-person: pid(4) + conf(4) + trans(12) + betas(40) + expr(40) + verts(125700)
+_PER_PERSON = 4 + 4 + 12 + 40 + 40 + 10475 * 3 * 4
+
+
+def _make_person(pid: int = 7) -> SMPLXPerson:
+    rng = np.random.default_rng(seed=42)
+    return SMPLXPerson(
+        pid=pid,
+        confidence=0.83,
+        translation=np.array([0.1, 0.2, 0.3], dtype=np.float32),
+        betas=rng.standard_normal(10).astype(np.float32),
+        expression=rng.standard_normal(10).astype(np.float32),
+        vertices_3d=rng.standard_normal((10475, 3)).astype(np.float32),
+    )
+
+
+def test_serialize_person_layout():
+    sender = SMPLXTCPSender.__new__(SMPLXTCPSender)
+    p = _make_person()
+    # _serialize_persons returns bytes starting with MAGIC + n_persons header
+    payload = SMPLXTCPSender._serialize_persons([p])
+
+    assert len(payload) == _HEADER + _PER_PERSON
+
+    # Check MAGIC and n_persons header
+    assert payload[:4] == b"SMPX"
+    (n_persons,) = struct.unpack_from("<i", payload, 4)
+    assert n_persons == 1
+
+    # Parse per-person fields starting at offset 8
+    base = _HEADER
+    pid, conf = struct.unpack_from("<if", payload, base)
+    assert pid == 7
+    assert abs(conf - 0.83) < 1e-5
+
+    # Reparse translation and compare
+    trans = np.frombuffer(payload, dtype="<f4", count=3, offset=base + 8)
+    np.testing.assert_allclose(trans, p.translation, rtol=0, atol=0)
+
+    # Reparse vertices and compare
+    verts = np.frombuffer(
+        payload, dtype="<f4", count=10475 * 3, offset=base + 8 + 12 + 40 + 40
+    ).reshape(10475, 3)
+    np.testing.assert_allclose(verts, p.vertices_3d, rtol=0, atol=0)
+
+
+def test_serialize_person_round_trip_handles_non_contiguous_input():
+    """Vertex arrays that come from slicing / transpose must still serialize cleanly."""
+    sender = SMPLXTCPSender.__new__(SMPLXTCPSender)
+    p = _make_person()
+    # Force a non-contiguous view:
+    p.vertices_3d = p.vertices_3d[::1, :].T.T
+    payload = SMPLXTCPSender._serialize_persons([p])
+    assert len(payload) == _HEADER + _PER_PERSON
+    base = _HEADER
+    verts = np.frombuffer(
+        payload, dtype="<f4", count=10475 * 3, offset=base + 8 + 12 + 40 + 40
+    ).reshape(10475, 3)
+    np.testing.assert_allclose(verts, p.vertices_3d, rtol=0, atol=0)