diff --git a/tests/data/test963 b/tests/data/test963
index b3a0051903..5d3bae7b56 100644
--- a/tests/data/test963
+++ b/tests/data/test963
@@ -23,7 +23,7 @@ IDN
 codeset-utf8
 </features>
 <setenv>
-LC_ALL
+LC_ALL=en_US.UTF-8
 LC_CTYPE=en_US.UTF-8
 </setenv>
 <name>