diff --git a/t/t3030-merge-recursive.sh b/t/t3030-merge-recursive.sh
index 34794f8a70..806fdccce1 100755
--- a/t/t3030-merge-recursive.sh
+++ b/t/t3030-merge-recursive.sh
@@ -312,7 +312,7 @@ test_expect_success 'merge-recursive result' '
 
 '
 
-test_expect_success 'fail if the index has unresolved entries' '
+test_expect_success C_LOCALE_OUTPUT 'fail if the index has unresolved entries' '
 
 	rm -fr [abcd] &&
 	git checkout -f "$c1" &&