--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2009-10-10  Eric Blake  <ebb9@byu.net>
 
+	test-dup2: enhance test
+	* tests/test-dup2.c (main): Also check AT_FDCWD.
+
 	test-stat-time: avoid more spurious failures
 	* tests/test-stat-time.c (nap): Wait for 15ms rather than 2ms, for
 	xfs; and avoid race if the two timestamps cross quantization edge.

--- a/tests/test-dup2.c
+++ b/tests/test-dup2.c
@@ -80,6 +80,15 @@
   ASSERT (dup2 (fd, fd) == fd);
   ASSERT (is_open (fd));
 
+  /* The source must be valid.  */
+  errno = 0;
+  ASSERT (dup2 (-1, fd) == -1);
+  ASSERT (errno == EBADF);
+  errno = 0;
+  ASSERT (dup2 (AT_FDCWD, fd) == -1);
+  ASSERT (errno == EBADF);
+  ASSERT (is_open (fd));
+
   /* If the source is not open, then the destination is unaffected.  */
   errno = 0;
   ASSERT (dup2 (fd + 1, fd + 1) == -1);