diff --git a/test/cpp_extensions/open_registration_extension/custom_device/csrc/extension.cpp b/test/cpp_extensions/open_registration_extension.cpp
similarity index 100%
rename from test/cpp_extensions/open_registration_extension/custom_device/csrc/extension.cpp
rename to test/cpp_extensions/open_registration_extension.cpp
diff --git a/test/cpp_extensions/open_registration_extension/setup.py b/test/cpp_extensions/open_registration_extension/setup.py
index bf1de5b9a8d..fa8c1308c6c 100644
--- a/test/cpp_extensions/open_registration_extension/setup.py
+++ b/test/cpp_extensions/open_registration_extension/setup.py
@@ -1,5 +1,6 @@
 import distutils.command.clean
 import os
+import platform
 import shutil
 import sys
 from pathlib import Path
@@ -40,8 +41,11 @@ if __name__ == "__main__":
             CXX_FLAGS = ["/sdl"]
         else:
             CXX_FLAGS = ["/sdl", "/permissive-"]
-    else:
+    elif platform.machine() == "s390x":
+        # no -Werror on s390x due to newer compiler
         CXX_FLAGS = {"cxx": ["-g", "-Wall"]}
+    else:
+        CXX_FLAGS = {"cxx": ["-g", "-Wall", "-Werror"]}
 
     sources = list(CSRS_DIR.glob("*.cpp"))
 
diff --git a/test/run_test.py b/test/run_test.py
index baf915942a5..f2cc18d5139 100755
--- a/test/run_test.py
+++ b/test/run_test.py
@@ -1236,6 +1236,7 @@ CUSTOM_HANDLERS = {
     "test_ci_sanity_check_fail": run_ci_sanity_check,
     "test_autoload_enable": test_autoload_enable,
     "test_autoload_disable": test_autoload_disable,
+    "test_cpp_extensions_open_device_registration": run_test_with_openreg,
     "test_openreg": run_test_with_openreg,
     "test_transformers_privateuse1": run_test_with_openreg,
 }
diff --git a/test/cpp_extensions/open_registration_extension/test/test_open_device_registration.py b/test/test_cpp_extensions_open_device_registration.py
similarity index 98%
rename from test/cpp_extensions/open_registration_extension/test/test_open_device_registration.py
rename to test/test_cpp_extensions_open_device_registration.py
index c17fb91c559..4ec01bf6fce 100644
--- a/test/cpp_extensions/open_registration_extension/test/test_open_device_registration.py
+++ b/test/test_cpp_extensions_open_device_registration.py
@@ -1,16 +1,15 @@
 # Owner(s): ["module: cpp-extensions"]
 
 import _codecs
-import importlib
 import io
 import os
 import sys
 import tempfile
 import unittest
-from pathlib import Path
 from unittest.mock import patch
 
 import numpy as np
+import pytorch_openreg  # noqa: F401
 
 import torch
 import torch.testing._internal.common_utils as common
@@ -61,21 +60,18 @@ class TestCppExtensionOpenRgistration(common.TestCase):
 
     @classmethod
     def setUpClass(cls):
-        # load custom device extension
-        extension_root = Path(__file__).parent.parent
+        torch.testing._internal.common_utils.remove_cpp_extensions_build_root()
+
         cls.module = torch.utils.cpp_extension.load(
             name="custom_device_extension",
             sources=[
-                f"{extension_root}/custom_device/csrc/extension.cpp",
+                "cpp_extensions/open_registration_extension.cpp",
             ],
-            extra_include_paths=[],
+            extra_include_paths=["cpp_extensions"],
             extra_cflags=["-g"],
             verbose=True,
         )
 
-        # install / load pytorch_openreg extension
-        common.install_cpp_extension(extension_root=extension_root)
-        globals()["pytorch_openreg"] = importlib.import_module("pytorch_openreg")
         torch.utils.generate_methods_for_privateuse1_backend(for_storage=True)
 
     def test_base_device_registration(self):