tests: pin the amd/huggingfacenotorch extras and name the audit failure

security-audit.yml builds its hf-stack scan set by indexing
[huggingfacenotorch] out of pyproject.toml with no guard. The pip release
branch never had that extra, so advisory audit and the three pip
scan-packages jobs died on a bare KeyError from at least 2026-07-08 to
2026-07-27 without anyone reading it as a missing extra.

Add a contract test for both extras (existence, torch-free, bnb floor
excludes the NaN-at-decode range) plus a check that every extra the
workflow indexes actually exists, and give the workflow a message that
names the problem instead of a raw traceback.

tests/python/test_amd_extras_contract.py

@@ -0,0 +1,100 @@
+# SPDX-License-Identifier: AGPL-3.0-only
+# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved.
+
+"""Contract tests for the amd / huggingfacenotorch extras.
+
+security-audit.yml builds its hf-stack scan set by indexing
+[huggingfacenotorch] straight out of pyproject.toml. When the pip release
+branch shipped without that extra, four security jobs died on a bare
+KeyError for three weeks and nobody noticed, because the failure looked
+like a generic Python crash rather than a missing extra.
+"""
+
+from __future__ import annotations
+
+import re
+import sys
+from pathlib import Path
+
+import pytest
+from packaging.specifiers import SpecifierSet
+from packaging.version import Version
+
+REPO_ROOT = Path(__file__).resolve().parents[2]
+PYPROJECT = REPO_ROOT / "pyproject.toml"
+SECURITY_AUDIT = REPO_ROOT / ".github" / "workflows" / "security-audit.yml"
+
+# bnb <= 0.49.2 NaNs at decode shape on every AMD GPU; the ROCm 4-bit GEMV
+# fix (bnb PR #1887) first ships in 0.50.0.
+BNB_MIN = Version("0.50.0")
+
+
+def _extras() -> dict[str, list[str]]:
+    if sys.version_info >= (3, 11):
+        import tomllib
+    else:
+        tomllib = pytest.importorskip("tomli")
+    data = tomllib.loads(PYPROJECT.read_text(encoding = "utf-8"))
+    return data["project"]["optional-dependencies"]
+
+
+def _project_name(spec: str) -> str:
+    """Leading distribution name of a PEP 508 requirement, lowercased."""
+    return re.split(r"[<>=!~;\[\s@]", spec.strip(), maxsplit = 1)[0].strip().lower()
+
+
+class TestExtrasExist:
+    """Both extras must be present, on every branch."""
+
+    @pytest.mark.parametrize("name", ["huggingfacenotorch", "amd"])
+    def test_extra_present(self, name: str):
+        assert name in _extras(), f"pyproject.toml is missing the [{name}] extra"
+
+    def test_amd_pulls_the_no_torch_stack(self):
+        assert any(
+            s.replace(" ", "") == "unsloth[huggingfacenotorch]" for s in _extras()["amd"]
+        ), "the amd extra must pull unsloth[huggingfacenotorch]"
+
+
+class TestHuggingfaceNoTorchIsTorchFree:
+    """The whole point of the extra is that it names no torch distribution."""
+
+    @pytest.mark.parametrize("banned", ["torch", "torchvision"])
+    def test_no_torch_distribution(self, banned: str):
+        named = [s for s in _extras()["huggingfacenotorch"] if _project_name(s) == banned]
+        assert not named, f"[huggingfacenotorch] must not name {banned}: {named}"
+
+
+class TestAmdBitsandbytesFloor:
+    """Guards the NaN-at-decode range out of the AMD install path."""
+
+    def test_every_marker_line_excludes_the_broken_range(self):
+        specs = [s for s in _extras()["amd"] if _project_name(s) == "bitsandbytes"]
+        assert specs, "the amd extra must pin bitsandbytes"
+        for spec in specs:
+            requirement = spec.split(";", 1)[0].strip()
+            allowed = SpecifierSet(requirement[len("bitsandbytes"):].strip())
+            assert not allowed.contains(Version("0.49.2")), (
+                f"{requirement} still admits bnb 0.49.2, which NaNs at decode shape on AMD"
+            )
+            assert allowed.contains(BNB_MIN), f"{requirement} excludes the fixed release {BNB_MIN}"
+
+
+class TestSecurityAuditWorkflowStaysInSync:
+    """Every extra the audit workflow indexes has to actually exist.
+
+    This is the generic form of the failure: the workflow reaches into
+    pyproject.toml by name, so any rename or omission takes out the scan
+    jobs rather than the branch that caused it.
+    """
+
+    def test_indexed_extras_exist(self):
+        referenced = set(
+            re.findall(
+                r'optional-dependencies"\]\["([^"]+)"\]',
+                SECURITY_AUDIT.read_text(encoding = "utf-8"),
+            )
+        )
+        assert referenced, "expected security-audit.yml to index at least one extra"
+        missing = sorted(referenced - set(_extras()))
+        assert not missing, f"security-audit.yml indexes extras that pyproject.toml lacks: {missing}"