diff --git a/openbsc/tests/bsc-nat/bsc_nat_test.c b/openbsc/tests/bsc-nat/bsc_nat_test.c
index 65ff4f6..ab97db1 100644
--- a/openbsc/tests/bsc-nat/bsc_nat_test.c
+++ b/openbsc/tests/bsc-nat/bsc_nat_test.c
@@ -267,7 +267,11 @@
 static void verify_msg(struct msgb *out, const uint8_t *ref, int ref_len)
 {
 	if (out->len != ref_len) {
-		printf("FAIL: The size should match.\n");
+		printf("FAIL: The size should match: %d vs. %d\n",
+			out->len, ref_len);
+		printf("%s\n", osmo_hexdump(out->data, out->len));
+		printf("Wanted\n");
+		printf("%s\n", osmo_hexdump(ref, ref_len));
 		abort();
 	}