hide output to stderr

diff --git a/skeletons/tests/check-OIDs.c b/skeletons/tests/check-OIDs.c
index 7916730..a9066a9 100644
--- a/skeletons/tests/check-OIDs.c
+++ b/skeletons/tests/check-OIDs.c
@@ -121,7 +121,7 @@
 	int ret;
 	int i;
 
-	printf("Encoding (R) {");
+	fprintf(stderr, "Encoding (R) {");
 	for(i = 0; i < acount; i++) {
 		printf(" %u", arcs[i]);
 	}
@@ -158,7 +158,7 @@
 	int ret;
 	int i;
 
-	printf("Encoding (O) {");
+	fprintf(stderr, "Encoding (O) {");
 	for(i = 0; i < acount; i++) {
 		printf(" %u", arcs[i]);
 	}