diff --git a/tests/graph_storage/array_sorted_list/sorted_list.c b/tests/graph_storage/array_sorted_list/sorted_list.c
index 2614784..462ed80 100644
--- a/tests/graph_storage/array_sorted_list/sorted_list.c
+++ b/tests/graph_storage/array_sorted_list/sorted_list.c
@@ -293,12 +293,30 @@ ALL_Array_setitem(ALL_Array * self
             PyErr_SetString(PyExc_MemoryError, "failed to allocate new node");
             return NULL;
         }
+        result = ll_insert_value(&(self->lists[j]), i);
+        if(result == 2)
+        {
+            PyErr_SetString(PyExc_ValueError, "element is already set");
+            return NULL;
+        }
+        if(result == 1)
+        {
+            PyErr_SetString(PyExc_MemoryError, "failed to allocate new node");
+            return NULL;
+        }
         Py_RETURN_NONE;
     }
     else
     {
         result = ll_delete_value(&(self->lists[i]), j);
 
+        if(result)
+        {
+            PyErr_SetString(PyExc_ValueError, "element is not set");
+            return NULL;
+        }
+        result = ll_delete_value(&(self->lists[j]), i);
+
         if(result)
         {
             PyErr_SetString(PyExc_ValueError, "element is not set");