diff --git a/test/ctl/string_test.cc b/test/ctl/string_test.cc
index 264edbbbc..1a35cfda3 100644
--- a/test/ctl/string_test.cc
+++ b/test/ctl/string_test.cc
@@ -308,10 +308,11 @@ main()
         s.append(" world");
         if (s != "hello world")
             return 63;
-        for (int i = 0; i < 4; ++i) {
+        for (int i = 0; i < 10; ++i) {
             s.append(" world");
         }
-        if (s != "hello world world world world world") {
+        if (s != "hello world world world world world world world world world "
+            "world world") {
             return 64;
         }
     }