Migrate cuda_pathfinder tests from os.path to pathlib

Part 4 of the series proposed in #2410.

Filesystem predicates and path joining in the pathfinder tests now go through
pathlib: os.path.isfile/isdir become Path.is_file()/is_dir(), os.path.basename
becomes Path.name, os.path.join becomes Path joining, and the site-packages
check uses Path.parts instead of splitting on os.path.sep.

site_pkg_rel.replace("/", os.sep) is dropped in test_find_static_lib.py: Path
already accepts forward slashes on Windows.

Two files are left out on purpose. test_find_nvidia_binaries.py moves with
part 3, whose signature changes it depends on. test_search_steps.py is being
edited by #2489 (part 1), so converting it here would only create a conflict.

Left on the stdlib modules: glob.glob in test_find_nvidia_headers.py, which
expands an absolute pattern from the header catalog (Path.glob needs a base
dir, and the wildcard is not pinned to the last component); os.pathsep in
test_ctk_root_discovery.py, which builds PYTHONPATH, not a path; and os.sep in
test_utils_env_vars.py, which builds a trailing separator on purpose.

Signed-off-by: LeSingh1 <sshaurya914@gmail.com>

Author: LeSingh1

cuda_pathfinder/tests/test_ctk_root_discovery.py

@@ -6,6 +6,7 @@
 import subprocess
 import sys
 import textwrap
+from pathlib import Path
 
 import pytest
 
@@ -427,7 +428,7 @@ def test_resolve_ctk_root_via_canary_none_when_probe_fails(mocker):
 def test_resolve_ctk_root_via_canary_none_when_unrecognized(mocker):
     mocker.patch(
         f"{_MODULE}._resolve_system_loaded_abs_path_in_subprocess",
-        return_value=os.path.join(os.sep, "weird", "path", "libcudart.so.13"),
+        return_value=str(Path(os.sep, "weird", "path", "libcudart.so.13")),
     )
     assert resolve_ctk_root_via_canary("cudart") is None
 

cuda_pathfinder/tests/test_driver_lib_loading.py

@@ -9,6 +9,7 @@
 """
 
 import os
+from pathlib import Path
 
 import pytest
 from child_load_nvidia_dynamic_lib_helper import (
@@ -157,7 +158,7 @@ def raise_child_process_failed():
         abs_path = payload.abs_path
         assert abs_path is not None
         info_summary_append(f"abs_path={quote_for_shell(abs_path)}")
-        assert os.path.isfile(abs_path)
+        assert Path(abs_path).is_file()
 
 
 def test_real_query_driver_cuda_version(info_summary_append):

cuda_pathfinder/tests/test_find_bitcode_lib.py

@@ -66,7 +66,7 @@ def _located_bitcode_lib_asserts(located_bitcode_lib):
     assert isinstance(located_bitcode_lib.filename, str)
     assert isinstance(located_bitcode_lib.found_via, str)
     assert located_bitcode_lib.found_via in ("site-packages", "conda", "CUDA_PATH")
-    assert os.path.isfile(located_bitcode_lib.abs_path)
+    assert Path(located_bitcode_lib.abs_path).is_file()
 
 
 @pytest.mark.usefixtures("clear_find_bitcode_lib_cache")
@@ -83,10 +83,10 @@ def test_locate_bitcode_lib(info_summary_append, libname):
 
     info_summary_append(f"{lib_path=!r}")
     _located_bitcode_lib_asserts(located_lib)
-    assert os.path.isfile(lib_path)
+    assert Path(lib_path).is_file()
     assert lib_path == located_lib.abs_path
     expected_filename = located_lib.filename
-    assert os.path.basename(lib_path) == expected_filename
+    assert Path(lib_path).name == expected_filename
 
 
 @pytest.mark.usefixtures("clear_find_bitcode_lib_cache")
@@ -156,7 +156,7 @@ def test_find_bitcode_lib_not_found_error_includes_cuda_home_directory_listing(m
         find_bitcode_lib("device")
 
     message = str(exc_info.value)
-    expected_missing_file = os.path.join(str(lib_dir), _bitcode_lib_filename("device"))
+    expected_missing_file = lib_dir / _bitcode_lib_filename("device")
     assert f"No such file: {expected_missing_file}" in message
     assert f'listdir("{lib_dir}"):' in message
     assert "README.txt" in message

cuda_pathfinder/tests/test_find_nvidia_headers.py

@@ -138,12 +138,12 @@ def test_locate_non_ctk_headers(info_summary_append, libname):
     info_summary_append(f"{hdr_dir=!r}")
     if hdr_dir:
         _located_hdr_dir_asserts(located_hdr_dir)
-        assert os.path.isdir(hdr_dir)
-        assert os.path.isfile(os.path.join(hdr_dir, SUPPORTED_HEADERS_NON_CTK[libname]))
+        hdr_dir_path = Path(hdr_dir)
+        assert hdr_dir_path.is_dir()
+        assert (hdr_dir_path / SUPPORTED_HEADERS_NON_CTK[libname]).is_file()
     if have_distribution_for(libname):
         assert hdr_dir is not None
-        hdr_dir_parts = hdr_dir.split(os.path.sep)
-        assert "site-packages" in hdr_dir_parts
+        assert "site-packages" in Path(hdr_dir).parts
     elif STRICTNESS == "all_must_work":
         assert hdr_dir is not None
         if conda_prefix := os.environ.get("CONDA_PREFIX"):
@@ -152,6 +152,8 @@ def test_locate_non_ctk_headers(info_summary_append, libname):
             inst_dirs = SUPPORTED_INSTALL_DIRS_NON_CTK.get(libname)
             if inst_dirs is not None:
                 for inst_dir in inst_dirs:
+                    # Absolute glob pattern: Path.glob needs a separate base dir,
+                    # and the wildcard is not pinned to the last component.
                     globbed = glob.glob(inst_dir)
                     if hdr_dir in globbed:
                         break
@@ -172,9 +174,10 @@ def test_locate_ctk_headers(info_summary_append, libname):
     info_summary_append(f"{hdr_dir=!r}")
     if hdr_dir:
         _located_hdr_dir_asserts(located_hdr_dir)
-        assert os.path.isdir(hdr_dir)
+        hdr_dir_path = Path(hdr_dir)
+        assert hdr_dir_path.is_dir()
         h_filename = SUPPORTED_HEADERS_CTK[libname]
-        assert os.path.isfile(os.path.join(hdr_dir, h_filename))
+        assert (hdr_dir_path / h_filename).is_file()
     if STRICTNESS == "all_must_work":
         if libname == "cudla":
             skip_if_missing_libnvcudla_so(libname, timeout=30)

cuda_pathfinder/tests/test_find_static_lib.py

@@ -52,7 +52,7 @@ def _located_static_lib_asserts(located_static_lib):
     assert isinstance(located_static_lib.filename, str)
     assert isinstance(located_static_lib.found_via, str)
     assert located_static_lib.found_via in ("site-packages", "conda", "CUDA_PATH")
-    assert os.path.isfile(located_static_lib.abs_path)
+    assert Path(located_static_lib.abs_path).is_file()
 
 
 @pytest.mark.usefixtures("clear_find_static_lib_cache")
@@ -69,10 +69,10 @@ def test_locate_static_lib(info_summary_append, libname):
 
     info_summary_append(f"abs_path={quote_for_shell(lib_path)}")
     _located_static_lib_asserts(located_lib)
-    assert os.path.isfile(lib_path)
+    assert Path(lib_path).is_file()
     assert lib_path == located_lib.abs_path
     expected_filename = located_lib.filename
-    assert os.path.basename(lib_path) == expected_filename
+    assert Path(lib_path).name == expected_filename
 
 
 @pytest.mark.usefixtures("clear_find_static_lib_cache")
@@ -81,7 +81,7 @@ def test_locate_static_lib_search_order(monkeypatch, tmp_path):
     conda_rel_path = CUDADEVRT_INFO["conda_rel_paths"][0]
 
     site_pkg_rel = CUDADEVRT_INFO["site_packages_dirs"][0]
-    site_packages_lib_dir = tmp_path / "site-packages" / Path(site_pkg_rel.replace("/", os.sep))
+    site_packages_lib_dir = tmp_path / "site-packages" / Path(site_pkg_rel)
     site_packages_path = _make_static_lib_file(site_packages_lib_dir, filename)
 
     conda_prefix = tmp_path / "conda-prefix"
@@ -167,7 +167,7 @@ def test_find_static_lib_not_found_error_includes_cuda_home_directory_listing(mo
         find_static_lib("cudadevrt")
 
     message = str(exc_info.value)
-    expected_missing_file = os.path.join(str(lib_dir), filename)
+    expected_missing_file = lib_dir / filename
     assert f"No such file: {expected_missing_file}" in message
     assert f'listdir("{lib_dir}"):' in message
     assert "README.txt" in message

cuda_pathfinder/tests/test_load_nvidia_dynamic_lib.py

@@ -3,6 +3,7 @@
 
 import os
 import platform
+from pathlib import Path
 
 import pytest
 from child_load_nvidia_dynamic_lib_helper import (
@@ -159,4 +160,4 @@ def raise_child_process_failed():
         abs_path = payload.abs_path
         assert abs_path is not None
         info_summary_append(f"abs_path={quote_for_shell(abs_path)}")
-        assert os.path.isfile(abs_path)  # double-check the abs_path
+        assert Path(abs_path).is_file()  # double-check the abs_path

cuda_pathfinder/tests/test_utils_find_sub_dirs.py

@@ -1,7 +1,7 @@
 # SPDX-FileCopyrightText: Copyright (c) 2025 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
-import os
+from pathlib import Path
 
 import pytest
 
@@ -77,7 +77,7 @@ def test_empty_parent_paths():
 def test_empty_sub_dirs(test_tree):
     parent_paths = test_tree["parent_paths"]
     result = find_sub_dirs(parent_paths, ())
-    expected = [p for p in parent_paths if os.path.isdir(p)]
+    expected = [p for p in parent_paths if Path(p).is_dir()]
     assert sorted(result) == sorted(expected)