diff --git a/t/spectest.data b/t/spectest.data
index e91a8f74..c75e7c05 100644
--- a/t/spectest.data
+++ b/t/spectest.data
@@ -551,6 +551,7 @@ S32-str/split.t
 S32-str/split-simple.t
 S32-str/sprintf.t
 S32-str/substr.t
+S32-str/substr-rw.t
 S32-str/trim.t
 S32-str/uc.t
 S32-str/ucfirst.t