diff --git a/tests/utils/stl/test/format.py b/tests/utils/stl/test/format.py
index 042112cef10..e5e5b2774df 100644
--- a/tests/utils/stl/test/format.py
+++ b/tests/utils/stl/test/format.py
@@ -65,7 +65,7 @@ def _getEnvLst(sourcePath, localConfig):
 def _isLegalDirectory(sourcePath, test_subdirs):
     for prefix in test_subdirs:
         common = os.path.normpath(os.path.commonpath((sourcePath, prefix)))
-        if common == sourcePath or common == prefix:
+        if os.path.samefile(common, sourcePath) or os.path.samefile(common, prefix):
             return True
 
     return False