style: fix ruff F401 lint errors for side-effect imports

Author: zhangyue

src/ascend/custom_kernel/csrc/ops/rms_norm/test/benchmark_rms_norm_msprof.py

@@ -5,7 +5,6 @@
 import json
 import os
 import subprocess
-import sys
 
 
 CASES_FILE = os.path.join(os.path.dirname(__file__), "rms_norm_cases.jsonl")

src/ascend/custom_kernel/csrc/ops/rms_norm/test/run_rms_norm_case.py

@@ -3,7 +3,7 @@
 import argparse
 import json
 import torch
-import torch_npu
+import torch_npu  # noqa: F401  Registers NPU device.
 import ascend_kernel  # noqa: F401
 
 

src/ascend/custom_kernel/csrc/ops/rms_norm/test/run_rms_norm_precision_report.py

@@ -2,7 +2,7 @@
 
 import json
 import torch
-import torch_npu
+import torch_npu  # noqa: F401  Registers NPU device.
 import ascend_kernel  # noqa: F401
 
 

src/ascend/custom_kernel/csrc/ops/rms_norm/test/test_rms_norm_precision.py

@@ -2,7 +2,7 @@
 
 import pytest
 import torch
-import torch_npu
+import torch_npu  # noqa: F401  Registers NPU device.
 import ascend_kernel  # noqa: F401
 
 

src/ascend/custom_kernel/tests/test_add_rms_norm.py

@@ -1,7 +1,7 @@
 """Correctness tests for custom AscendC add_rms_norm kernel."""
 
 import torch
-import torch_npu
+import torch_npu  # noqa: F401  Registers NPU device.
 import pytest
 
 

src/ascend/custom_kernel/tests/test_rms_norm.py

@@ -2,7 +2,7 @@
 
 import pytest
 import torch
-import torch_npu
+import torch_npu  # noqa: F401  Registers NPU device.
 import ascend_kernel  # noqa: F401  Loads `libascend_kernel.so` into `torch.ops.npu`.