test(cuda.core): isolate fstat failure from pytest capture

cuda_core/tests/test_program_cache.py

@@ -2132,6 +2132,7 @@ def _failing_open(path, flags, *args, **kwargs):
         assert not utime_calls, "os.utime must not run after os.open fails"
 
 
+@pytest.mark.human_reviewed
 def test_filestream_touch_atime_swallows_fstat_failure(tmp_path, monkeypatch):
     """The best-effort atime bump swallows an ``os.fstat`` failure after the fd
     was opened: the read still returns the cached bytes, closes the fd, and
@@ -2171,10 +2172,21 @@ def _failing_fstat(fd):
             raise OSError("fstat refused")
 
         utime_calls = []
-        monkeypatch.setattr(_os, "open", _recording_open)
-        monkeypatch.setattr(_os, "close", _recording_close)
-        monkeypatch.setattr(_os, "fstat", _failing_fstat)
-        monkeypatch.setattr(_os, "utime", lambda *a, **k: utime_calls.append((a, k)))
+
+        # Patch os only as _file_stream sees it: pytest's own output capture also calls os.fstat.
+        class _PatchedOs:
+            open = staticmethod(_recording_open)
+            close = staticmethod(_recording_close)
+            fstat = staticmethod(_failing_fstat)
+
+            @staticmethod
+            def utime(*a, **k):
+                utime_calls.append((a, k))
+
+            def __getattr__(self, name):
+                return getattr(_os, name)
+
+        monkeypatch.setattr(_program_cache._file_stream, "os", _PatchedOs())
 
         assert cache[b"k"] == b"v"
         assert fstat_calls, "the atime bump should have attempted os.fstat"