feat(lab): freeze RAVNOVES00 R0 acceptance contract

tests/test_e37_acceptance_contract.py

@@ -0,0 +1,98 @@
+from __future__ import annotations
+
+from collections import Counter
+
+import pytest
+
+from k1link.compute.e37_acceptance_contract import (
+    E37AcceptanceContractError,
+    assign_split,
+    derive_reference_labels,
+)
+
+
+def _decision(
+    *,
+    detector: str,
+    ownership: str,
+    cause: str | None = None,
+    effective_stratum: str | None = "agree",
+) -> dict[str, object]:
+    return {
+        "detector_assessment": detector,
+        "point_ownership": ownership,
+        "cause_code": cause,
+        "effective_stratum": effective_stratum,
+    }
+
+
+def test_r0_reference_projection_keeps_dimensions_independent() -> None:
+    assert derive_reference_labels(
+        _decision(detector="valid", ownership="object"),
+        None,
+    ) == ("object-present", "object-associated", "current")
+    assert derive_reference_labels(
+        _decision(
+            detector="false-positive",
+            ownership="surface-or-background",
+            cause="time_mismatch",
+        ),
+        None,
+    ) == ("background-or-noise", "rejected-nonobject", "stale")
+    assert derive_reference_labels(
+        _decision(
+            detector="not-applicable",
+            ownership="insufficient-support",
+            effective_stratum="camera-only",
+        ),
+        None,
+    ) == ("unknown", "insufficient-support", "unavailable")
+
+
+def test_human_exception_only_overrides_the_ambiguous_reference() -> None:
+    ambiguous = _decision(
+        detector="insufficient-evidence",
+        ownership="insufficient-evidence",
+        effective_stratum=None,
+    )
+    assert derive_reference_labels(ambiguous, "object-present") == (
+        "occupied-environment",
+        "independent-occupied",
+        "unavailable",
+    )
+    assert derive_reference_labels(ambiguous, "background-or-noise") == (
+        "background-or-noise",
+        "rejected-nonobject",
+        "unavailable",
+    )
+
+
+def test_split_is_deterministic_balanced_and_complete() -> None:
+    rows = [
+        {
+            "item_id": f"item-{index:03d}",
+            "source_stratum": "agree" if index % 2 else "conflict",
+            "range_bucket": "near" if index % 3 else "far",
+        }
+        for index in range(60)
+    ]
+    first = assign_split(
+        rows,
+        seed="frozen-seed",
+        validation_fraction=0.3,
+    )
+    second = assign_split(
+        list(reversed(rows)),
+        seed="frozen-seed",
+        validation_fraction=0.3,
+    )
+    assert first == second
+    assert set(first) == {row["item_id"] for row in rows}
+    assert Counter(first.values())["validation"] == 18
+
+
+def test_split_rejects_mutable_or_invalid_fraction() -> None:
+    with pytest.raises(E37AcceptanceContractError):
+        assign_split([], seed="", validation_fraction=0.3)
+    with pytest.raises(E37AcceptanceContractError):
+        assign_split([], seed="seed", validation_fraction=0.9)