diff --git a/tests/dlloader-api.at b/tests/dlloader-api.at
index 37c8984..8d04e7b 100644
--- a/tests/dlloader-api.at
+++ b/tests/dlloader-api.at
@@ -47,7 +47,8 @@ first_open (lt_user_data data, const char *filename, lt_dladvise advise)
 
   if (!filename || strcmp (filename, "first"))
     {
-      printf ("first_open denies a request\n");
+      printf ("first_open denies request for \"%s\"\n",
+        filename ? filename : "(null)");
       lt_dlseterror (LT_ERROR_FILE_NOT_FOUND);
       return NULL;
     }
@@ -113,7 +114,8 @@ last_open (lt_user_data data, const char *filename, lt_dladvise advise)
 
   if (!filename || strcmp (filename, "last"))
     {
-      printf ("last_open denies a request\n");
+      printf ("last_open denies request for \"%s\"\n",
+        filename ? filename : "(null)");
       lt_dlseterror (LT_ERROR_FILE_NOT_FOUND);
       return NULL;
     }