--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2010-03-21  Bruno Haible  <bruno@clisp.org>
 
+	Tests for module 'ttyname_r'.
+	* modules/ttyname_r-tests: New file.
+	* tests/test-ttyname_r.c: New file.
+
 	New module 'ttyname_r'.
 	* lib/ttyname_r.c: New file.
 	* m4/ttyname_r.m4: New file.

new file mode 100644
--- /dev/null
+++ b/modules/ttyname_r-tests
@@ -0,0 +1,12 @@
+Files:
+tests/test-ttyname_r.c
+tests/signature.h
+tests/macros.h
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-ttyname_r
+check_PROGRAMS += test-ttyname_r

new file mode 100644
--- /dev/null
+++ b/tests/test-ttyname_r.c
@@ -0,0 +1,51 @@
+/* Test of ttyname_r(3).
+   Copyright (C) 2010 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
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#include <unistd.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (ttyname_r, int, (int, char *, size_t));
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "macros.h"
+
+int
+main (void)
+{
+  int fd;
+  char buf[100];
+
+  /* Open the controlling tty of the current process.  */
+  fd = open ("/dev/tty", O_RDONLY);
+  if (fd < 0)
+    {
+      fprintf (stderr, "Skipping test: cannot open controlling tty\n");
+      return 77;
+    }
+
+  ASSERT (ttyname_r (fd, buf, 1) == ERANGE);
+
+  ASSERT (ttyname_r (fd, buf, sizeof (buf)) == 0);
+  ASSERT (memcmp (buf, "/dev/", 5) == 0);
+
+  return 0;
+}