diff --git a/test/unit/etharp/test_etharp.c b/test/unit/etharp/test_etharp.c
index 86370aa0..8eb506c1 100644
--- a/test/unit/etharp/test_etharp.c
+++ b/test/unit/etharp/test_etharp.c
@@ -32,15 +32,6 @@ etharp_remove_all(void)
   }
 }
 
-static err_t
-dummy_input_function(struct pbuf *p, struct netif *inp)
-{
-  LWIP_UNUSED_ARG(p);
-  LWIP_UNUSED_ARG(inp);
-  fail("this netif should have no input");
-  return ERR_VAL;
-}
-
 static err_t
 default_netif_linkoutput(struct netif *netif, struct pbuf *p)
 {
@@ -71,7 +62,7 @@ default_netif_add(void)
 
   fail_unless(netif_default == NULL);
   netif_set_default(netif_add(&test_netif, &test_ipaddr, &test_netmask,
-                              &test_gw, NULL, default_netif_init, dummy_input_function));
+                              &test_gw, NULL, default_netif_init, NULL));
   netif_set_up(&test_netif);
 }
 
diff --git a/test/unit/ip6/test_ip6.c b/test/unit/ip6/test_ip6.c
index 79ce5f92..d4386984 100644
--- a/test/unit/ip6/test_ip6.c
+++ b/test/unit/ip6/test_ip6.c
@@ -16,15 +16,6 @@
 static struct netif test_netif6;
 static int linkoutput_ctr;
 
-static err_t
-dummy_input_function(struct pbuf *p, struct netif *inp)
-{
-  LWIP_UNUSED_ARG(p);
-  LWIP_UNUSED_ARG(inp);
-  fail("this netif should have no input");
-  return ERR_VAL;
-}
-
 static err_t
 default_netif_linkoutput(struct netif *netif, struct pbuf *p)
 {
@@ -51,7 +42,7 @@ default_netif_add(void)
 {
   struct netif *n;
   fail_unless(netif_default == NULL);
-  n = netif_add_noaddr(&test_netif6, NULL, default_netif_init, dummy_input_function);
+  n = netif_add_noaddr(&test_netif6, NULL, default_netif_init, NULL);
   fail_unless(n == &test_netif6);
   netif_set_default(&test_netif6);
 }