--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2011-12-01  Ben Walton  <bwalton@artsci.utoronto.ca>
+
+	Add a test suite for the sethostname module.
+	* modules/sethostname-tests: New file.  A test program
+	for the sethostname module.
+	* tests/test-sethostname.c: Likewise.
+
 2011-12-03  Bruno Haible  <bruno@clisp.org>
 
 	Tweak last commit.

new file mode 100644
--- /dev/null
+++ b/modules/sethostname-tests
@@ -0,0 +1,13 @@
+Files:
+tests/signature.h
+tests/test-sethostname.c
+tests/macros.h
+
+Depends-on:
+sys_types
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-sethostname
+check_PROGRAMS += test-sethostname

new file mode 100644
--- /dev/null
+++ b/tests/test-sethostname.c
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2011 Free Software Foundation, Inc.
+ * Written by Ben Walton.
+ *
+ * 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 (sethostname, int, (const char *, size_t));
+
+/* for HOST_NAME_MAX */
+#include <limits.h>
+/* for uid_t */
+#include <sys/types.h>
+/* for strlen */
+#include <string.h>
+
+#include <errno.h>
+#include <stdio.h>
+
+#include "macros.h"
+
+#define TESTHOSTNAME "gnulib-hostname"
+
+/* mingw and MSVC 9 lack geteuid, so setup a value that will indicate
+   we don't have root privilege since we wouldn't know whether to
+   expect success or failure when setting a name anyway*/
+#if !HAVE_GETEUID
+# define geteuid() ((uid_t) -1)
+#endif
+
+int
+main (int argc, char *argv[] _GL_UNUSED)
+{
+  char origname[HOST_NAME_MAX];
+  char newname[HOST_NAME_MAX];
+  char longname[HOST_NAME_MAX + 2];
+  int rcg, rcs, i;
+
+  /* skip the tests if we don't have root privilege.  this does not
+     consider things like CAP_SYS_ADMIN (linux) or PRIV_SYS_ADMIN
+     (solaris), etc.  systems without a working geteuid (mingw, MSVC
+     9) will always skip this test. */
+  if (geteuid() != 0)
+    return 0;
+
+  /* we want to ensure we can do a get/set/get check to ensure the
+     change is accepted. record the current name so it can be restored
+     later */
+  ASSERT(gethostname (origname, sizeof (origname)) == 0);
+
+  /* try setting a valid hostname.  if it fails -1/ENOSYS, we will
+     skip the test for long names as this is an indication we're using
+     the stub function that doesn't do anything on this platform. */
+  rcs = sethostname (TESTHOSTNAME, strlen (TESTHOSTNAME));
+
+  if (rcs != 0)
+    {
+      if (rcs == -1 && errno == ENOSYS)
+	return 0;
+      else
+	{
+	  printf ("error setting valid hostname.\n");
+	  return 1;
+	}
+    }
+  else
+    {
+      ASSERT (gethostname (newname, sizeof (newname)) == 0);
+
+      /* if we don't get back what we put in, there is no need to
+	 restore the original name as we will assume it was not
+	 properly changed. */
+      if (strcmp (newname, TESTHOSTNAME) != 0)
+	{
+	  printf ("set/get comparison failed.\n");
+	  return 1;
+	}
+    }
+
+  /* glibc does allow setting a zero length name, so the lower bound
+     needs no test. validate that we are constrained by
+     HOST_NAME_MAX */
+  for (i = 0; i < (HOST_NAME_MAX + 1); i++)
+    longname[i] = 'a';
+
+  longname[i] = '\0';
+
+  rcs = sethostname ((const char *) longname, (HOST_NAME_MAX + 1));
+
+  if (rcs != -1)
+    {
+      /* attempt to restore the original name. */
+      sethostname (origname, strlen (origname));
+      printf ("expected failure when setting very long hostname.\n");
+      return 1;
+    }
+
+  /* restore the original name. */
+  sethostname (origname, strlen (origname));
+
+  return 0;
+}