add _cuda_headers_available() guard to conftest files

Add a helper that skips tests when no CUDA path is set, but
asserts that the include/ subdirectory exists when one is — surfacing
stale or incomplete toolkit roots at collection time instead of
letting them fail later in compilation.

Applied in both the root conftest.py and cuda_core/tests/conftest.py.

Made-with: Cursor

Author: rwgk

conftest.py

@@ -2,13 +2,30 @@
 # SPDX-License-Identifier: Apache-2.0
 
 
+import os
+
 import pytest
 
 from cuda.pathfinder import get_cuda_path_or_home
 
 
+# Please keep in sync with the copy in cuda_core/tests/conftest.py.
+def _cuda_headers_available() -> bool:
+    """Return True if CUDA headers are available, False if no CUDA path is set.
+
+    Raises AssertionError if a CUDA path is set but has no include/ subdirectory.
+    """
+    cuda_path = get_cuda_path_or_home()
+    if cuda_path is None:
+        return False
+    assert os.path.isdir(os.path.join(cuda_path, "include")), (
+        f"CUDA path {cuda_path} does not contain an 'include' subdirectory"
+    )
+    return True
+
+
 def pytest_collection_modifyitems(config, items):  # noqa: ARG001
-    cuda_home = get_cuda_path_or_home()
+    have_headers = _cuda_headers_available()
     for item in items:
         nodeid = item.nodeid.replace("\\", "/")
 
@@ -32,6 +49,10 @@ def pytest_collection_modifyitems(config, items):  # noqa: ARG001
         ):
             item.add_marker(pytest.mark.cython)
 
-            # Gate core cython tests on CUDA_HOME
-            if "core" in item.keywords and not cuda_home:
-                item.add_marker(pytest.mark.skip(reason="CUDA_HOME not set; skipping core cython tests"))
+            # Gate core cython tests on CUDA_PATH
+            if "core" in item.keywords and not have_headers:
+                item.add_marker(
+                    pytest.mark.skip(
+                        reason="Environment variable CUDA_PATH or CUDA_HOME is not set: skipping core cython tests"
+                    )
+                )

cuda_core/tests/conftest.py

@@ -254,7 +254,22 @@ def test_something(memory_resource_factory):
     return request.param
 
 
+# Please keep in sync with the copy in the top-level conftest.py.
+def _cuda_headers_available() -> bool:
+    """Return True if CUDA headers are available, False if no CUDA path is set.
+
+    Raises AssertionError if a CUDA path is set but has no include/ subdirectory.
+    """
+    cuda_path = get_cuda_path_or_home()
+    if cuda_path is None:
+        return False
+    assert os.path.isdir(os.path.join(cuda_path, "include")), (
+        f"CUDA path {cuda_path} does not contain an 'include' subdirectory"
+    )
+    return True
+
+
 skipif_need_cuda_headers = pytest.mark.skipif(
-    get_cuda_path_or_home() is None,
+    not _cuda_headers_available(),
     reason="need CUDA header",
 )