diff --git a/test/unit/lwip_check.h b/test/unit/lwip_check.h
index 73468ddf..522a9c3e 100644
--- a/test/unit/lwip_check.h
+++ b/test/unit/lwip_check.h
@@ -37,6 +37,6 @@ int lwip_unittests_run(void)
 /* helper functions */
 #define SKIP_POOL(x) (1 << x)
 #define SKIP_HEAP    (1 << MEMP_MAX)
-void lwip_check_ensure_no_alloc(uint32_t skip);
+void lwip_check_ensure_no_alloc(unsigned int skip);
 
 #endif /* LWIP_HDR_LWIP_CHECK_H */
diff --git a/test/unit/lwip_unittests.c b/test/unit/lwip_unittests.c
index f0dce30d..b371764f 100644
--- a/test/unit/lwip_unittests.c
+++ b/test/unit/lwip_unittests.c
@@ -33,12 +33,10 @@ Suite* create_suite(const char* name, testfunc *tests, size_t num_tests, SFun se
   return s;
 }
 
-void lwip_check_ensure_no_alloc(uint32_t skip)
+void lwip_check_ensure_no_alloc(unsigned int skip)
 {
   int i;
-  uint32_t mask;
-
-  fail_unless(skip != 0);
+  unsigned int mask;
 
   if (!(skip & SKIP_HEAP)) {
     fail_unless(lwip_stats.mem.used == 0);