Fix os.access behavior for symlinks under Windows

- found after enabling symlink tests for Windows

Author: mrbean-bremen

CHANGES.md

@@ -22,6 +22,7 @@ The released versions correspond to PyPI releases.
   (see [#1120](../../issues/1120))
 * fixed a regression that could break tests under Posix in Python 3.12
   (see [#1126](../../issues/1126))
+* fixed behavior for `os.access` for symlinks under Windows
 
 ## [Version 5.7.4](https://pypi.python.org/pypi/pyfakefs/5.7.4) (2025-01-14)
 Minor bugfix release.

pyfakefs/fake_os.py

@@ -1021,8 +1021,8 @@ def access(
         mode: int,
         *,
         dir_fd: Optional[int] = None,
-        effective_ids: bool = False,
-        follow_symlinks: bool = True,
+        effective_ids: Optional[bool] = None,
+        follow_symlinks: Optional[bool] = None,
     ) -> bool:
         """Check if a file exists and has the specified permissions.
 
@@ -1039,10 +1039,17 @@ def access(
         Returns:
             bool, `True` if file is accessible, `False` otherwise.
         """
-        if effective_ids and self.filesystem.is_windows_fs:
+        if effective_ids is not None and self.filesystem.is_windows_fs:
             raise NotImplementedError(
                 "access: effective_ids unavailable on this platform"
             )
+        if follow_symlinks is None:
+            # different behavior under Windows
+            follow_symlinks = not self.filesystem.is_windows_fs
+        elif self.filesystem.is_windows_fs:
+            raise NotImplementedError(
+                "access: follow_symlinks unavailable on this platform"
+            )
         path = self._path_with_dir_fd(path, self.access, dir_fd)
         try:
             stat_result = self.stat(path, follow_symlinks=follow_symlinks)

pyfakefs/tests/fake_filesystem_shutil_test.py

@@ -27,7 +27,7 @@
 
 from pyfakefs import fake_filesystem_unittest
 from pyfakefs.helpers import get_uid, set_uid, is_root, IS_PYPY
-from pyfakefs.tests.test_utils import RealFsTestMixin
+from pyfakefs.tests.test_utils import RealFsTestMixin, skip_if_symlink_not_supported
 
 is_windows = sys.platform == "win32"
 
@@ -244,7 +244,7 @@ def test_copystat(self):
     @unittest.skipIf(IS_PYPY, "Functionality not supported in PyPy")
     def test_copystat_symlinks(self):
         """Regression test for #799"""
-        self.skip_if_symlink_not_supported()
+        skip_if_symlink_not_supported()
         f = self.make_path("xyzzy")
         self.create_file(f)
         sym1 = self.make_path("sym1")
@@ -434,7 +434,7 @@ def test_raises_if_source_and_dest_are_the_same_file(self):
             shutil.copyfile(src_file, dst_file)
 
     def test_raises_if_dest_is_a_symlink_to_src(self):
-        self.skip_if_symlink_not_supported()
+        skip_if_symlink_not_supported()
         src_file = self.make_path("foo")
         dst_file = self.make_path("bar")
         contents = "contents of file"

pyfakefs/tests/fake_filesystem_test.py

@@ -34,7 +34,12 @@
     OSType,
 )
 from pyfakefs.helpers import IS_WIN
-from pyfakefs.tests.test_utils import TestCase, RealFsTestCase, time_mock
+from pyfakefs.tests.test_utils import (
+    TestCase,
+    RealFsTestCase,
+    time_mock,
+    skip_if_symlink_not_supported,
+)
 
 
 class FakeDirectoryUnitTest(TestCase):
@@ -2039,7 +2044,7 @@ def test_that_unc_paths_are_auto_mounted(self):
 
 class ConvenienceMethodTest(RealFsTestCase):
     def test_create_link_with_non_existent_parent(self):
-        self.skip_if_symlink_not_supported()
+        skip_if_symlink_not_supported()
         file1_path = self.make_path("test_file1")
         link_path = self.make_path("nonexistent", "test_file2")
 
@@ -2050,7 +2055,7 @@ def test_create_link_with_non_existent_parent(self):
         self.assertTrue(self.filesystem.exists(link_path))
 
     def test_create_symlink_with_non_existent_parent(self):
-        self.skip_if_symlink_not_supported()
+        skip_if_symlink_not_supported()
         file1_path = self.make_path("test_file1")
         link_path = self.make_path("nonexistent", "test_file2")
 
@@ -2163,7 +2168,7 @@ def test_cannot_overwrite_symlink_with_dir(self):
                 self.filesystem.add_real_directory(root_dir, target_path="/root/")
 
     def test_symlink_is_merged(self):
-        self.skip_if_symlink_not_supported()
+        skip_if_symlink_not_supported()
         self.filesystem.create_dir(os.path.join("/", "root", "foo"))
         with self.create_real_paths() as root_dir:
             link_path = os.path.join(root_dir, "link.txt")
@@ -2428,7 +2433,7 @@ def test_add_existing_real_directory_symlink(self):
         )
 
     def test_add_existing_real_directory_symlink_target_path(self):
-        self.skip_if_symlink_not_supported()
+        skip_if_symlink_not_supported()
         real_directory = self._setup_temp_directory()
         symlinks = [
             (
@@ -2453,7 +2458,7 @@ def test_add_existing_real_directory_symlink_target_path(self):
         self.assertTrue(self.filesystem.exists("/path/fixtures/symlink_file_relative"))
 
     def test_add_existing_real_directory_symlink_lazy_read(self):
-        self.skip_if_symlink_not_supported()
+        skip_if_symlink_not_supported()
         real_directory = self._setup_temp_directory()
         symlinks = [
             (

pyfakefs/tests/fake_filesystem_vs_real_test.py

@@ -23,7 +23,7 @@
 import unittest
 
 from pyfakefs import fake_filesystem, fake_os, fake_open
-from pyfakefs.helpers import IS_PYPY
+from pyfakefs.tests.test_utils import skip_if_symlink_not_supported
 
 
 def sep(path):
@@ -81,6 +81,7 @@ def _create_test_file(self, file_type, path, contents=None):
             fh.close()
         # l for symlink, h for hard link
         if file_type in ("l", "h"):
+            contents = sep(contents)
             real_target, fake_target = (contents, contents)
             # If it begins with '/', make it relative to the base. You can't go
             # creating files in / for the real file system.
@@ -375,13 +376,16 @@ def assertOsPathMethodBehaviorMatches(
 
     def assertAllOsBehaviorsMatch(self, path):
         path = sep(path)
-        os_method_names = [] if self.is_windows else ["readlink"]
+        os_method_names = ["readlink"]
         os_method_names_no_args = ["getcwd"]
-        os_path_method_names = ["isabs", "isdir"]
-        if not self.is_windows:
-            os_path_method_names += ["islink", "lexists"]
-        if not self.is_windows or not IS_PYPY:
-            os_path_method_names += ["isfile", "exists"]
+        os_path_method_names = [
+            "isabs",
+            "isdir",
+            "islink",
+            "lexists",
+            "isfile",
+            "exists",
+        ]
 
         wrapped_methods = [
             ["access", self._access_real, self._access_fake],
@@ -557,34 +561,33 @@ def test_file_with_binary_contents(self):
         self._create_test_file("b", "aFile", b"some contents")
         self.assertAllOsBehaviorsMatch("aFile")
 
-    @unittest.skipIf(TestCase.is_windows, "no symlink in Windows")
     def test_sym_link_to_empty_file(self):
+        skip_if_symlink_not_supported()
         self._create_test_file("f", "aFile")
         self._create_test_file("l", "link_to_empty", "aFile")
         self.assertAllOsBehaviorsMatch("link_to_empty")
 
-    @unittest.skipIf(TestCase.is_windows, "no symlink in Windows")
     def test_hard_link_to_empty_file(self):
+        skip_if_symlink_not_supported()
         self._create_test_file("f", "aFile")
         self._create_test_file("h", "link_to_empty", "aFile")
         self.assertAllOsBehaviorsMatch("link_to_empty")
 
-    @unittest.skipIf(TestCase.is_windows, "no symlink in Windows")
     def test_sym_link_to_real_file(self):
+        skip_if_symlink_not_supported()
         self._create_test_file("f", "aFile", "some contents")
         self._create_test_file("l", "link_to_file", "aFile")
         self.assertAllOsBehaviorsMatch("link_to_file")
 
-    @unittest.skipIf(TestCase.is_windows, "no symlink in Windows")
     def test_hard_link_to_real_file(self):
+        skip_if_symlink_not_supported()
         self._create_test_file("f", "aFile", "some contents")
         self._create_test_file("h", "link_to_file", "aFile")
         self.assertAllOsBehaviorsMatch("link_to_file")
 
-    @unittest.skipIf(TestCase.is_windows, "no symlink in Windows")
     def test_broken_sym_link(self):
+        skip_if_symlink_not_supported()
         self._create_test_file("l", "broken_link", "broken")
-        self._create_test_file("l", "loop", "/a/loop")
         self.assertAllOsBehaviorsMatch("broken_link")
 
     def test_file_in_a_folder(self):
@@ -593,16 +596,16 @@ def test_file_in_a_folder(self):
         self._create_test_file("f", "a/b/file", "contents")
         self.assertAllOsBehaviorsMatch("a/b/file")
 
-    @unittest.skipIf(TestCase.is_windows, "no symlink in Windows")
     def test_absolute_sym_link_to_folder(self):
+        skip_if_symlink_not_supported()
         self._create_test_file("d", "a")
         self._create_test_file("d", "a/b")
         self._create_test_file("f", "a/b/file", "contents")
         self._create_test_file("l", "a/link", "/a/b")
         self.assertAllOsBehaviorsMatch("a/link/file")
 
-    @unittest.skipIf(TestCase.is_windows, "no symlink in Windows")
     def test_link_to_folder_after_chdir(self):
+        skip_if_symlink_not_supported()
         self._create_test_file("d", "a")
         self._create_test_file("d", "a/b")
         self._create_test_file("f", "a/b/file", "contents")
@@ -613,51 +616,51 @@ def test_link_to_folder_after_chdir(self):
         self.fake_os.chdir(fake_dir)
         self.assertAllOsBehaviorsMatch("file")
 
-    @unittest.skipIf(TestCase.is_windows, "no symlink in Windows")
     def test_relative_sym_link_to_folder(self):
+        skip_if_symlink_not_supported()
         self._create_test_file("d", "a")
         self._create_test_file("d", "a/b")
         self._create_test_file("f", "a/b/file", "contents")
         self._create_test_file("l", "a/link", "b")
         self.assertAllOsBehaviorsMatch("a/link/file")
 
-    @unittest.skipIf(TestCase.is_windows, "no symlink in Windows")
     def test_sym_link_to_parent(self):
+        skip_if_symlink_not_supported()
         # Soft links on HFS+ / OS X behave differently.
-        if os.uname()[0] != "Darwin":
+        if sys.platform != "darwin":
             self._create_test_file("d", "a")
             self._create_test_file("d", "a/b")
             self._create_test_file("l", "a/b/c", "..")
             self.assertAllOsBehaviorsMatch("a/b/c")
 
-    @unittest.skipIf(TestCase.is_windows, "no symlink in Windows")
     def test_path_through_sym_link_to_parent(self):
+        skip_if_symlink_not_supported()
         self._create_test_file("d", "a")
         self._create_test_file("f", "a/target", "contents")
         self._create_test_file("d", "a/b")
         self._create_test_file("l", "a/b/c", "..")
         self.assertAllOsBehaviorsMatch("a/b/c/target")
 
-    @unittest.skipIf(TestCase.is_windows, "no symlink in Windows")
     def test_sym_link_to_sibling_directory(self):
+        skip_if_symlink_not_supported()
         self._create_test_file("d", "a")
         self._create_test_file("d", "a/b")
         self._create_test_file("d", "a/sibling_of_b")
         self._create_test_file("f", "a/sibling_of_b/target", "contents")
         self._create_test_file("l", "a/b/c", "../sibling_of_b")
         self.assertAllOsBehaviorsMatch("a/b/c/target")
 
-    @unittest.skipIf(TestCase.is_windows, "no symlink in Windows")
-    def test_sym_link_to_sibling_directory_non_existant_file(self):
+    def test_sym_link_to_sibling_directory_non_existent_file(self):
+        skip_if_symlink_not_supported()
         self._create_test_file("d", "a")
         self._create_test_file("d", "a/b")
         self._create_test_file("d", "a/sibling_of_b")
         self._create_test_file("f", "a/sibling_of_b/target", "contents")
         self._create_test_file("l", "a/b/c", "../sibling_of_b")
         self.assertAllOsBehaviorsMatch("a/b/c/file_does_not_exist")
 
-    @unittest.skipIf(TestCase.is_windows, "no symlink in Windows")
     def test_broken_sym_link_to_sibling_directory(self):
+        skip_if_symlink_not_supported()
         self._create_test_file("d", "a")
         self._create_test_file("d", "a/b")
         self._create_test_file("d", "a/sibling_of_b")