Index: uspace/app/tester/mm/mapping1.c
===================================================================
--- uspace/app/tester/mm/mapping1.c	(revision 8e3498b351ae109f7ad16592a1f108e3bd44c829)
+++ uspace/app/tester/mm/mapping1.c	(revision c1694b6b243b360b5f1fbf0629b5e7d4f7f4a515)
@@ -30,4 +30,5 @@
 #include <stdlib.h>
 #include <stddef.h>
+#include <str_error.h>
 #include <as.h>
 #include <errno.h>
@@ -74,6 +75,6 @@
 		int rc = as_get_physical_mapping(page_start, NULL);
 		if (rc != expected_rc) {
-			TPRINTF("as_get_physical_mapping() = %d != %d\n",
-			    rc, expected_rc);
+			TPRINTF("as_get_physical_mapping() = %s != %s\n",
+			    str_error_name(rc), str_error_name(expected_rc));
 			return false;
 		}