diff --git a/test-suite/tests/ports.test b/test-suite/tests/ports.test
index 9690122b5..2d25f420a 100644
--- a/test-suite/tests/ports.test
+++ b/test-suite/tests/ports.test
@@ -1,7 +1,7 @@
 ;;;; ports.test --- test suite for Guile I/O ports     -*- scheme -*-
 ;;;; Jim Blandy <jimb@red-bean.com> --- May 1999
 ;;;;
-;;;; 	Copyright (C) 1999, 2001, 2004, 2006 Free Software Foundation, Inc.
+;;;; 	Copyright (C) 1999, 2001, 2004, 2006, 2007 Free Software Foundation, Inc.
 ;;;; 
 ;;;; This program is free software; you can redistribute it and/or modify
 ;;;; it under the terms of the GNU General Public License as published by
@@ -538,6 +538,17 @@
 	(while (not (eof-object? (read-char port))))
 	(= 8 (port-column port))))))
 
+(with-test-prefix "port-line"
+
+  ;; in guile 1.8.1 and earlier port-line was truncated to an int, whereas
+  ;; scm_t_port actually holds a long; this restricted the range on 64-bit
+  ;; systems
+  (pass-if "set most-positive-fixnum/2"
+    (let ((n    (quotient most-positive-fixnum 2))
+	  (port (open-output-string)))
+      (set-port-line! port n)
+      (eqv? n (port-line port)))))
+
 ;;;
 ;;; seek
 ;;;