1 files changed, 1 insertions, 1 deletions

diff --git a/auto_tests/onion_test.c b/auto_tests/onion_test.c
index bf764f67..5989df17 100644
--- a/auto_tests/onion_test.c
+++ b/auto_tests/onion_test.c
@@ -449,7 +449,7 @@ START_TEST(test_announce)
 
     for (i = 0; i < NUM_ONIONS; ++i) {
         onions[i] = new_onions(i + 34655);
-        ck_assert_msg(onions[i] != nullptr, "Failed to create onions. %u");
+        ck_assert_msg(onions[i] != nullptr, "Failed to create onions. %u", i);
     }
 
     IP ip = get_loopback();