--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2010-01-09  Bruno Haible  <bruno@clisp.org>
+
+	Tests for module 'getlogin_r'.
+	* modules/getlogin_r-tests: New file.
+	* tests/test-getlogin_r.c: New file.
+
 2010-01-09  Jim Meyering  <meyering@redhat.com>
 
 	maint.mk: extend proper_name_utf8-vs-LIBICONV-checking rule

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

new file mode 100644
--- /dev/null
+++ b/tests/test-getlogin_r.c
@@ -0,0 +1,73 @@
+/* Test of getting user name.
+   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/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2010.  */
+
+#include <config.h>
+
+#include <unistd.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (getlogin_r, int, (char *, size_t));
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "macros.h"
+
+int
+main (void)
+{
+  /* Test with a large enough buffer.  */
+  char buf[1024];
+
+  ASSERT (getlogin_r (buf, sizeof (buf)) == 0);
+
+  /* Compare against the value from the environment.  */
+#if !((defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__)
+  /* Unix platform */
+  {
+    const char *name = getenv ("LOGNAME");
+    if (name == NULL || name[0] == '\0')
+      name = getenv ("USER");
+    if (name != NULL && name[0] != '\0')
+      ASSERT (strcmp (buf, name) == 0);
+  }
+#endif
+#if (defined _WIN32 || defined __WIN32__) && !defined __CYGWIN__
+  /* Native Windows platform.
+     Note: This test would fail on Cygwin in an ssh session, because sshd
+     sets USERNAME=SYSTEM.  */
+  {
+    const char *name = getenv ("USERNAME");
+    if (name != NULL && name[0] != '\0')
+      ASSERT (strcmp (buf, name) == 0);
+  }
+#endif
+
+  /* Test with a small buffer.  */
+  {
+    char smallbuf[1024];
+    size_t n = strlen (buf);
+    size_t i;
+
+    for (i = 0; i <= n; i++)
+      ASSERT (getlogin_r (smallbuf, i) == ERANGE);
+  }
+
+  return 0;
+}