chore: introduce tests intended to validate the behavior of longpath-support in optional symlink-resolution for windows

Signed-off-by: Stephen Mackenzie <maxnbk@users.noreply.github.com>

Author: maxnbk

src/rez/tests/test_utils_filesystem.py

@@ -198,6 +198,24 @@ def test_drive_letter_case_folded(self):
         )
 
 
+def _windows_longpaths_enabled() -> bool:
+    """Return True if the Windows LongPathsEnabled registry key is set.
+
+    When False, the Win32 API cannot open paths longer than MAX_PATH (260
+    chars) without an explicit ``\\?\\`` extended-length prefix.
+    """
+    try:
+        import winreg
+        with winreg.OpenKey(
+            winreg.HKEY_LOCAL_MACHINE,
+            r"SYSTEM\CurrentControlSet\Control\FileSystem",
+        ) as key:
+            value, _ = winreg.QueryValueEx(key, "LongPathsEnabled")
+            return bool(value)
+    except OSError:
+        return False
+
+
 @unittest.skipIf(
     platform_.name != "windows",
     "Windows symlink/junction resolution tests are Windows-only.",
@@ -267,3 +285,21 @@ def test_non_symlink_path_unchanged(self):
 
         result = canonical_path(d, platform=self._mock_windows_platform())
         self.assertEqual(result, d.lower())
+
+    def test_long_path_symlink_resolved(self):
+        """canonical_path resolves a symlink whose target exceeds MAX_PATH (260
+        chars) on hosts with LongPathsEnabled set in the registry."""
+        if not _windows_longpaths_enabled():
+            self.skipTest(
+                "LongPathsEnabled not set in registry; skipping long-path test."
+            )
+
+        # self.root is typically ~60-70 chars; 220 'a' chars puts the full
+        # target path comfortably past the 260-char Win32 MAX_PATH limit.
+        target = os.path.join(self.root, "a" * 220)
+        link = os.path.join(self.root, "longpath_link")
+        os.makedirs(target)
+        os.symlink(target, link, target_is_directory=True)
+
+        result = canonical_path(link, platform=self._windows_platform_mock())
+        self.assertEqual(result, target.lower())