diff --git a/scripts/sanitycheck b/scripts/sanitycheck
index d55bf021533..20b4b02d0c0 100755
--- a/scripts/sanitycheck
+++ b/scripts/sanitycheck
@@ -1740,7 +1740,7 @@ class TestCase:
     def get_unique(self, testcase_root, workdir, name):
 
         canonical_testcase_root = os.path.realpath(testcase_root)
-        if canonical_testcase_root.startswith(canonical_zephyr_base):
+        if Path(canonical_zephyr_base) in Path(canonical_testcase_root).parents:
             # This is in ZEPHYR_BASE, so include path in name for uniqueness
             # FIXME: We should not depend on path of test for unique names.
             relative_tc_root = os.path.relpath(canonical_testcase_root,