diff --git a/test/test-loop-handles.c b/test/test-loop-handles.c
index 81271fed..4f506dad 100644
--- a/test/test-loop-handles.c
+++ b/test/test-loop-handles.c
@@ -107,22 +107,28 @@ static int timeout_cb_called = 0;
 
 
 static void timeout_cb(oio_req_t *req, int64_t skew, int status) {
+  int r;
+
   ASSERT(req == &timeout_req);
   ASSERT(status == 0);
 
   timeout_cb_called++;
 
-  oio_timeout(req, TIMEOUT);
+  r = oio_timeout(req, TIMEOUT);
+  ASSERT(r == 0);
 }
 
 
 static void idle_2_cb(oio_handle_t* handle, int status) {
+  int r;
+
   ASSERT(handle == &idle_2_handle);
   ASSERT(status == 0);
 
   idle_2_cb_called++;
 
-  oio_close(handle);
+  r = oio_close(handle);
+  ASSERT(r == 0);
 }
 
 
@@ -138,6 +144,8 @@ static void idle_2_close_cb(oio_handle_t* handle, int status){
 
 
 static void idle_1_cb(oio_handle_t* handle, int status) {
+  int r;
+
   ASSERT(handle != NULL);
   ASSERT(status == 0);
 
@@ -145,8 +153,10 @@ static void idle_1_cb(oio_handle_t* handle, int status) {
 
   /* Init idle_2 and make it active */
   if (!idle_2_is_active) {
-    oio_idle_init(&idle_2_handle, idle_2_close_cb, NULL);
-    oio_idle_start(&idle_2_handle, idle_2_cb);
+    r = oio_idle_init(&idle_2_handle, idle_2_close_cb, NULL);
+    ASSERT(r == 0);
+    r = oio_idle_start(&idle_2_handle, idle_2_cb);
+    ASSERT(r == 0);
     idle_2_is_active = 1;
     idle_2_cb_started++;
   }
@@ -154,7 +164,8 @@ static void idle_1_cb(oio_handle_t* handle, int status) {
   idle_1_cb_called++;
 
   if (idle_1_cb_called % 5 == 0) {
-    oio_idle_stop(handle);
+    r = oio_idle_stop(handle);
+    ASSERT(r == 0);
     idles_1_active--;
   }
 }
@@ -169,7 +180,7 @@ static void idle_1_close_cb(oio_handle_t* handle, int status){
 
 
 static void check_cb(oio_handle_t* handle, int status) {
-  int i;
+  int i, r;
 
   ASSERT(handle == &check_handle);
   ASSERT(status == 0);
@@ -180,24 +191,30 @@ static void check_cb(oio_handle_t* handle, int status) {
   if (loop_iteration < ITERATIONS) {
     /* Make some idle watchers active */
     for (i = 0; i < 1 + (loop_iteration % IDLE_COUNT); i++) {
-      oio_idle_start(&idle_1_handles[i], idle_1_cb);
+      r = oio_idle_start(&idle_1_handles[i], idle_1_cb);
+      ASSERT(r == 0);
       idles_1_active++;
     }
 
   } else {
     /* End of the test - close all handles */
-    oio_close(&prepare_1_handle);
-    oio_close(&check_handle);
-    oio_close(&prepare_2_handle);
+    r = oio_close(&prepare_1_handle);
+    ASSERT(r == 0);
+    r = oio_close(&check_handle);
+    ASSERT(r == 0);
+    r = oio_close(&prepare_2_handle);
+    ASSERT(r == 0);
 
     for (i = 0; i < IDLE_COUNT; i++) {
-      oio_close(&idle_1_handles[i]);
+      r = oio_close(&idle_1_handles[i]);
+      ASSERT(r == 0);
     }
 
     /* This handle is closed/recreated every time, close it only if it is */
     /* active.*/
     if (idle_2_is_active) {
-      oio_close(&idle_2_handle);
+      r = oio_close(&idle_2_handle);
+      ASSERT(r == 0);
     }
   }
 
@@ -214,6 +231,8 @@ static void check_close_cb(oio_handle_t* handle, int status){
 
 
 static void prepare_2_cb(oio_handle_t* handle, int status) {
+  int r;
+
   ASSERT(handle == &prepare_2_handle);
   ASSERT(status == 0);
 
@@ -226,7 +245,8 @@ static void prepare_2_cb(oio_handle_t* handle, int status) {
   /* (loop_iteration % 2 == 0) cannot be true. */
   ASSERT(loop_iteration % 2 != 0);
 
-  oio_prepare_stop(handle);
+  r = oio_prepare_stop(handle);
+  ASSERT(r == 0);
 
   prepare_2_cb_called++;
 }
@@ -241,6 +261,8 @@ static void prepare_2_close_cb(oio_handle_t* handle, int status){
 
 
 static void prepare_1_cb(oio_handle_t* handle, int status) {
+  int r;
+
   ASSERT(handle == &prepare_1_handle);
   ASSERT(status == 0);
 
@@ -248,7 +270,8 @@ static void prepare_1_cb(oio_handle_t* handle, int status) {
   ASSERT(idle_2_is_active == 0);
 
   if (loop_iteration % 2 == 0) {
-    oio_prepare_start(&prepare_2_handle, prepare_2_cb);
+    r = oio_prepare_start(&prepare_2_handle, prepare_2_cb);
+    ASSERT(r == 0);
   }
 
   prepare_1_cb_called++;
@@ -275,21 +298,28 @@ static oio_buf alloc_cb(oio_handle_t* handle, size_t size) {
 
 TEST_IMPL(loop_handles) {
   int i;
+  int r;
 
   oio_init(alloc_cb);
 
-  oio_prepare_init(&prepare_1_handle, prepare_1_close_cb, NULL);
-  oio_prepare_start(&prepare_1_handle, prepare_1_cb);
+  r = oio_prepare_init(&prepare_1_handle, prepare_1_close_cb, NULL);
+  ASSERT(r == 0);
+  r = oio_prepare_start(&prepare_1_handle, prepare_1_cb);
+  ASSERT(r == 0);
 
-  oio_check_init(&check_handle, check_close_cb, NULL);
-  oio_check_start(&check_handle, check_cb);
+  r = oio_check_init(&check_handle, check_close_cb, NULL);
+  ASSERT(r == 0);
+  r = oio_check_start(&check_handle, check_cb);
+  ASSERT(r == 0);
 
   /* initialize only, prepare_2 is started by prepare_1_cb */
-  oio_prepare_init(&prepare_2_handle, prepare_2_close_cb, NULL);
+  r = oio_prepare_init(&prepare_2_handle, prepare_2_close_cb, NULL);
+  ASSERT(r == 0);
 
   for (i = 0; i < IDLE_COUNT; i++) {
     /* initialize only, idle_1 handles are started by check_cb */
-    oio_idle_init(&idle_1_handles[i], idle_1_close_cb, NULL);
+    r = oio_idle_init(&idle_1_handles[i], idle_1_close_cb, NULL);
+    ASSERT(r == 0);
   }
 
   /* don't init or start idle_2, both is done by idle_1_cb */
@@ -297,10 +327,12 @@ TEST_IMPL(loop_handles) {
   /* the timer callback is there to keep the event loop polling */
   /* unref it as it is not supposed to keep the loop alive */
   oio_req_init(&timeout_req, NULL, timeout_cb);
-  oio_timeout(&timeout_req, TIMEOUT);
+  r = oio_timeout(&timeout_req, TIMEOUT);
+  ASSERT(r == 0);
   oio_unref();
 
-  oio_run();
+  r = oio_run();
+  ASSERT(r == 0);
 
   ASSERT(loop_iteration == ITERATIONS);