Add material reference size regression tests

Author: fraware

tests/test_material_reference_sizes.py

@@ -0,0 +1,35 @@
+from ovk.core.materials import canonical_material_bytes, material_reference_from_payload
+from ovk.core.self_protection_compiler import compile_self_protection_obligation
+
+
+def test_material_reference_size_matches_canonical_payload_bytes() -> None:
+    payload = {"z": [1, 2, 3], "a": {"enabled": True}}
+    reference = material_reference_from_payload(
+        material_id="material-1",
+        kind="policy",
+        uri="ovk-material:test/policy",
+        payload=payload,
+        source_revision="abc",
+    )
+    assert reference.size_bytes == len(canonical_material_bytes(payload))
+    assert reference.size_bytes != len(reference.sha256)
+
+
+def test_self_protection_material_sizes_bind_each_payload() -> None:
+    data = {
+        "actor": {"type": "ai_agent", "id": "agent-1"},
+        "task": "preserve the gate",
+        "changed_files": [".github/workflows/ci.yml"],
+        "before": {"required_checks": ["ovk-verify"]},
+        "after": {"required_checks": ["ovk-verify"]},
+    }
+    obligation = compile_self_protection_obligation(
+        data,
+        repo="example/repo",
+        head_sha="head",
+        base_sha="base",
+    )
+    by_id = {item.material_id: item for item in obligation.materials}
+    assert by_id["self-protection-before"].size_bytes == len(canonical_material_bytes(data["before"]))
+    assert by_id["self-protection-after"].size_bytes == len(canonical_material_bytes(data["after"]))
+    assert by_id["self-protection-input"].size_bytes == len(canonical_material_bytes(data))