--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2011-09-20  Bruno Haible  <bruno@clisp.org>
 
+	Tests for function fputc().
+	* modules/fputc-tests: New file.
+	* tests/test-fputc.c: New file.
+	* modules/stdio-tests (Depends-on): Add fputc-tests.
+
 	Tests for function fgetc().
 	* modules/fgetc-tests: New file.
 	* tests/test-fgetc.c: New file.

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

new file mode 100644
--- /dev/null
+++ b/tests/test-fputc.c
@@ -0,0 +1,78 @@
+/* Test of fputc() function.
+   Copyright (C) 2011 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, 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, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#include <config.h>
+
+#include <stdio.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (fputc, int, (int, FILE *));
+
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include "macros.h"
+
+int
+main (int argc, char **argv)
+{
+  const char *filename = "test-fputc.txt";
+
+  /* Test that fputc() on an unbuffered stream sets errno if someone else
+     closes the stream fd behind the back of stdio.  */
+  {
+    FILE *fp = fopen (filename, "w");
+    ASSERT (fp != NULL);
+    setvbuf (fp, NULL, _IONBF, 0);
+    ASSERT (close (fileno (fp)) == 0);
+    errno = 0;
+    ASSERT (fputc ('x', fp) == EOF);
+    ASSERT (errno == EBADF);
+    fclose (fp);
+  }
+
+  /* Test that fputc() on an unbuffered stream sets errno if the stream
+     was constructed with an invalid file descriptor.  */
+  {
+    FILE *fp = fdopen (-1, "w");
+    if (fp != NULL)
+      {
+        setvbuf (fp, NULL, _IONBF, 0);
+        errno = 0;
+        ASSERT (fputc ('x', fp) == EOF);
+        ASSERT (errno == EBADF);
+        fclose (fp);
+      }
+  }
+  {
+    FILE *fp = fdopen (99, "w");
+    if (fp != NULL)
+      {
+        setvbuf (fp, NULL, _IONBF, 0);
+        errno = 0;
+        ASSERT (fputc ('x', fp) == EOF);
+        ASSERT (errno == EBADF);
+        fclose (fp);
+      }
+  }
+
+  /* Clean up.  */
+  unlink (filename);
+
+  return 0;
+}