new file mode 100644
--- /dev/null
+++ b/tests/test-mkdirat.c
@@ -0,0 +1,91 @@
+/* Tests of mkdirat.
+   Copyright (C) 2009 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 Eric Blake <ebb9@byu.net>, 2009.  */
+
+#include <config.h>
+
+#include <sys/stat.h>
+
+#include <fcntl.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define ASSERT(expr) \
+  do                                                                         \
+    {                                                                        \
+      if (!(expr))                                                           \
+        {                                                                    \
+          fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__);  \
+          fflush (stderr);                                                   \
+          abort ();                                                          \
+        }                                                                    \
+    }                                                                        \
+  while (0)
+
+#define BASE "test-mkdirat.t"
+
+#include "test-mkdir.h"
+
+static int dfd = AT_FDCWD;
+
+/* Wrapper to test mkdirat like mkdir.  */
+static int
+do_mkdir (char const *name, mode_t mode)
+{
+  return mkdirat (dfd, name, mode);
+}
+
+int
+main ()
+{
+  int result;
+
+  /* Clean up any trash from prior testsuite runs.  */
+  ASSERT (system ("rm -rf " BASE "*") == 0);
+
+  /* Test basic mkdir functionality.  */
+  result = test_mkdir (do_mkdir, false);
+  dfd = open (".", O_RDONLY);
+  ASSERT (0 <= dfd);
+  ASSERT (test_mkdir (do_mkdir, false) == result);
+
+  /* Tests specific to mkdirat.  */
+  ASSERT (mkdirat (dfd, BASE "dir1", 0700) == 0);
+  ASSERT (chdir (BASE "dir1") == 0);
+  ASSERT (close (dfd) == 0);
+  dfd = open ("..", O_RDONLY);
+  ASSERT (0 <= dfd);
+  ASSERT (mkdirat (dfd, BASE "dir2", 0700) == 0);
+  ASSERT (close (dfd) == 0);
+  errno = 0;
+  ASSERT (mkdirat (dfd, BASE "dir3", 0700) == -1);
+  ASSERT (errno == EBADF);
+  dfd = open ("/dev/null", O_RDONLY);
+  ASSERT (0 <= dfd);
+  errno = 0;
+  ASSERT (mkdirat (dfd, "dir3", 0700) == -1);
+  ASSERT (errno == ENOTDIR);
+  ASSERT (close (dfd) == 0);
+  ASSERT (chdir ("..") == 0);
+  ASSERT (rmdir (BASE "dir1") == 0);
+  ASSERT (rmdir (BASE "dir2") == 0);
+
+  return result;
+}