1 files changed, 53 insertions, 0 deletions
diff --git a/tests/test-dup.c b/tests/test-dup.c
new file mode 100644
index 00000000..884fbc60
--- /dev/null
+++ b/tests/test-dup.c
@@ -0,0 +1,53 @@
+/* Test duplicating a file descriptor.
+   Copyright (C) 2011-2024 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 <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+#include <unistd.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (dup, int, (int));
+
+#include <errno.h>
+#include <fcntl.h>
+
+#include "macros.h"
+
+int
+main (void)
+{
+  /* Test behaviour for invalid file descriptors.  */
+  {
+    errno = 0;
+    ASSERT (dup (-1) == -1);
+    ASSERT (errno == EBADF);
+  }
+  {
+    close (99);
+    errno = 0;
+    ASSERT (dup (99) == -1);
+    ASSERT (errno == EBADF);
+  }
+#ifdef AT_FDCWD
+  {
+    errno = 0;
+    ASSERT (dup (AT_FDCWD) == -1);
+    ASSERT (errno == EBADF);
+  }
+#endif
+
+  return test_exit_status;
+}