diff --git a/tests/test-utils.c b/tests/test-utils.c
index cbb931b..ccbe382 100644
--- a/tests/test-utils.c
+++ b/tests/test-utils.c
@@ -14,6 +14,7 @@
 
 struct mctp_binding_test {
 	struct mctp_binding binding;
+	uint8_t tx_storage[MCTP_PKTBUF_SIZE(MCTP_BTU)];
 };
 
 static int mctp_binding_test_tx(struct mctp_binding *b __attribute__((unused)),
@@ -35,6 +36,7 @@
 	test->binding.pkt_size = MCTP_PACKET_SIZE(MCTP_BTU);
 	test->binding.pkt_header = 0;
 	test->binding.pkt_trailer = 0;
+	test->binding.tx_storage = test->tx_storage;
 	return test;
 }
 
@@ -52,6 +54,7 @@
 	assert(pkt);
 	memcpy(mctp_pktbuf_hdr(pkt), buf, len);
 	mctp_bus_rx(&test->binding, pkt);
+	mctp_pktbuf_free(pkt);
 }
 
 void mctp_binding_test_register_bus(struct mctp_binding_test *binding,