Fix the field-id enum name in the nvml test helper supports_nvlink (#2560)

def supports_nvlink(device):
        fields = nvml.FieldValue(1)
        fields[0].field_id = nvml.FI.DEV_NVLINK_GET_STATE

There is no `FI` attribute on cuda.bindings.nvml. The enum is `FieldId`
(nvml.pyx:1229), with DEV_NVLINK_GET_STATE at nvml.pyx:1454, and the sibling
test uses the correct spelling: test_nvlink.py:19 does
`fields[0].field_id = nvml.FieldId.DEV_NVLINK_LINK_COUNT`.

So the helper raises AttributeError on its first line of real work. Nobody
has noticed because it has no callers -- a repo-wide grep for
`supports_nvlink` finds only its own definition. Contrast util.supports_ecc,
which is called from test_page_retirement.py.

Adds tests/nvml/test_util.py, which stubs nvml.device_get_field_values so the
helper can be exercised without an NVLink-capable device, and asserts both
that it returns True and that it queried FieldId.DEV_NVLINK_GET_STATE. It
fails with AttributeError before this change.

Author: LeSingh1

cuda_bindings/tests/nvml/test_util.py

@@ -0,0 +1,28 @@
+# SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+
+import pytest
+
+from cuda.bindings import nvml
+
+from . import util
+
+
+class _FakeFieldValue:
+    nvml_return = nvml.Return.SUCCESS
+
+
+@pytest.mark.agent_authored(model="claude-opus-5")
+def test_supports_nvlink_queries_a_real_field_id(monkeypatch):
+    """The helper has to name an enum that exists; nvml.FI never did."""
+    queried = {}
+
+    def fake_device_get_field_values(device, fields):
+        queried["field_id"] = fields[0].field_id
+        return [_FakeFieldValue()]
+
+    monkeypatch.setattr(nvml, "device_get_field_values", fake_device_get_field_values)
+
+    assert util.supports_nvlink(object()) is True
+    assert queried["field_id"] == nvml.FieldId.DEV_NVLINK_GET_STATE

cuda_bindings/tests/nvml/util.py

@@ -22,5 +22,5 @@ def supports_ecc(device):
 
 def supports_nvlink(device):
     fields = nvml.FieldValue(1)
-    fields[0].field_id = nvml.FI.DEV_NVLINK_GET_STATE
+    fields[0].field_id = nvml.FieldId.DEV_NVLINK_GET_STATE
     return nvml.device_get_field_values(device, fields)[0].nvml_return == nvml.Return.SUCCESS