diff --git a/tests/gnrc_sixlowpan_frag_sfr/mockup_netif.c b/tests/gnrc_sixlowpan_frag_sfr/mockup_netif.c
index c7ac366585..be2b71fb13 100644
--- a/tests/gnrc_sixlowpan_frag_sfr/mockup_netif.c
+++ b/tests/gnrc_sixlowpan_frag_sfr/mockup_netif.c
@@ -22,6 +22,7 @@
 #include "net/gnrc/netif/internal.h"
 #include "net/netdev_test.h"
 #include "sched.h"
+#include "test_utils/expect.h"
 #include "thread.h"
 
 #define _MSG_QUEUE_SIZE  (2)
@@ -35,7 +36,7 @@ static gnrc_netif_t _netif;
 
 void _common_set_up(void)
 {
-    assert(_mock_netif != NULL);
+    expect(_mock_netif != NULL);
     gnrc_ipv6_nib_init();
     gnrc_netif_acquire(_mock_netif);
     gnrc_ipv6_nib_init_iface(_mock_netif);
@@ -45,14 +46,14 @@ void _common_set_up(void)
 int _get_device_type(netdev_t *dev, void *value, size_t max_len)
 {
     (void)dev;
-    assert(max_len == sizeof(uint16_t));
+    expect(max_len == sizeof(uint16_t));
     *((uint16_t *)value) = NETDEV_TYPE_IEEE802154;
     return sizeof(uint16_t);
 }
 
 static int _get_netdev_proto(netdev_t *netdev, void *value, size_t max_len)
 {
-    assert(max_len == sizeof(gnrc_nettype_t));
+    expect(max_len == sizeof(gnrc_nettype_t));
     (void)netdev;
 
     *((gnrc_nettype_t *)value) = GNRC_NETTYPE_SIXLOWPAN;
@@ -62,7 +63,7 @@ static int _get_netdev_proto(netdev_t *netdev, void *value, size_t max_len)
 int _get_max_pdu_size(netdev_t *dev, void *value, size_t max_len)
 {
     (void)dev;
-    assert(max_len == sizeof(uint16_t));
+    expect(max_len == sizeof(uint16_t));
     *((uint16_t *)value) = 102U;
     return sizeof(uint16_t);
 }
@@ -70,7 +71,7 @@ int _get_max_pdu_size(netdev_t *dev, void *value, size_t max_len)
 int _get_src_len(netdev_t *dev, void *value, size_t max_len)
 {
     (void)dev;
-    assert(max_len == sizeof(uint16_t));
+    expect(max_len == sizeof(uint16_t));
     *((uint16_t *)value) = IEEE802154_LONG_ADDRESS_LEN;
     return sizeof(uint16_t);
 }
@@ -81,7 +82,7 @@ int _get_address_long(netdev_t *dev, void *value, size_t max_len)
                                     _LL4, _LL5, _LL6, _LL7 };
 
     (void)dev;
-    assert(max_len >= sizeof(addr));
+    expect(max_len >= sizeof(addr));
     memcpy(value, addr, sizeof(addr));
     return sizeof(addr);
 }
@@ -89,7 +90,7 @@ int _get_address_long(netdev_t *dev, void *value, size_t max_len)
 int _get_proto(netdev_t *dev, void *value, size_t max_len)
 {
     (void)dev;
-    assert(max_len == sizeof(gnrc_nettype_t));
+    expect(max_len == sizeof(gnrc_nettype_t));
     *((gnrc_nettype_t *)value) = GNRC_NETTYPE_SIXLOWPAN;
     return sizeof(gnrc_nettype_t);
 }
@@ -116,7 +117,7 @@ void _tests_init(void)
             &_netif, _mock_netif_stack, THREAD_STACKSIZE_DEFAULT,
             GNRC_NETIF_PRIO, "mockup_wpan", &_mock_netdev.netdev.netdev
         );
-    assert(res == 0);
+    expect(res == 0);
     _mock_netif = &_netif;
 }