test: use the shared guard instead of local copies

test_index had a private probe and test_refs repeated the same check
inline.

Author: Cyrus580529

test/test_index.py

@@ -40,7 +40,7 @@
 from git.util import Actor, cwd, hex_to_bin, rmtree
 
 from test.lib import TestBase, VirtualEnvironment, fixture, fixture_path, with_rw_directory, with_rw_repo, PathLikeMock
-from test.lib.helper import xfail_if_raises
+from test.lib.helper import symlinks_supported, xfail_if_raises
 
 HOOKS_SHEBANG = "#!/usr/bin/env sh\n"
 
@@ -175,19 +175,6 @@ def _decode(stdout):
 _win_bash_status = WinBashStatus.check()
 
 
-def _windows_supports_symlinks():
-    if sys.platform != "win32":
-        return False
-
-    with tempfile.TemporaryDirectory(prefix="gitpython-symlink-check-") as temp_dir:
-        link_path = osp.join(temp_dir, "link")
-        try:
-            os.symlink("missing-target", link_path)
-        except (NotImplementedError, OSError):
-            return False
-        return S_ISLNK(os.lstat(link_path)[ST_MODE])
-
-
 def _make_hook(git_dir, name, content, make_exec=True):
     """A helper to create a hook"""
     hp = hook_path(name, git_dir)
@@ -655,7 +642,7 @@ def _count_existing(self, repo, files):
     @with_rw_repo("0.1.6")
     def test_index_mutation(self, rw_repo):
         with xfail_if_raises(
-            sys.platform == "win32" and (Git().config("core.symlinks") == "true" or _windows_supports_symlinks()),
+            sys.platform == "win32" and (Git().config("core.symlinks") == "true" or symlinks_supported()),
             raises=(FileNotFoundError, GitCommandError),
             reason="Assumes symlinks are not created on Windows and opens a symlink to a nonexistent target.",
         ):

test/test_refs.py

@@ -28,7 +28,7 @@
 import git.refs as refs
 from git.util import Actor
 
-from test.lib import TestBase, with_rw_repo, PathLikeMock
+from test.lib import TestBase, requires_symlinks, with_rw_repo, PathLikeMock
 
 
 class TestRefs(TestBase):
@@ -780,6 +780,7 @@ def test_symbolic_reference_log_append_rejects_path_traversal(self):
                 )
                 assert not outside_path.exists()
 
+    @requires_symlinks
     def test_symbolic_reference_set_reference_rejects_symlink_escape(self):
         with tempfile.TemporaryDirectory() as tmp_dir:
             base_dir = Path(tmp_dir)
@@ -791,10 +792,7 @@ def test_symbolic_reference_set_reference_rejects_symlink_escape(self):
                 refs_heads_dir = Path(repo.common_dir) / "refs" / "heads"
                 refs_heads_dir.mkdir(parents=True, exist_ok=True)
                 symlink_path = refs_heads_dir / "link_out"
-                try:
-                    symlink_path.symlink_to(outside_dir, target_is_directory=True)
-                except (OSError, NotImplementedError) as ex:
-                    self.skipTest("symlinks unavailable on this platform: %s" % ex)
+                symlink_path.symlink_to(outside_dir, target_is_directory=True)
                 if osp.realpath(symlink_path / "escaped") == osp.abspath(symlink_path / "escaped"):
                     self.skipTest("realpath does not resolve directory symlinks on this platform")