/* Tests of unsetenv.

   Copyright (C) 2009-2017 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 <stdlib.h>

#include "signature.h"

SIGNATURE_CHECK (unsetenv, int, (char const *));

#include <errno.h>

#include <string.h>

#include <unistd.h>

#include "macros.h"

int

main (void)

{

  char entry[] = "b=2";

  /* Test removal when multiple entries present.  */

  ASSERT (putenv ((char *) "a=1") == 0);

  ASSERT (putenv (entry) == 0);

  entry[0] = 'a'; /* Unspecified what getenv("a") would be at this point.  */

  ASSERT (unsetenv ("a") == 0); /* Both entries will be removed.  */

  ASSERT (getenv ("a") == NULL);

  ASSERT (unsetenv ("a") == 0);

  /* Required to fail with EINVAL.  */

  errno = 0;

  ASSERT (unsetenv ("") == -1);

  ASSERT (errno == EINVAL);

  errno = 0;

  ASSERT (unsetenv ("a=b") == -1);

  ASSERT (errno == EINVAL);

#if 0

  /* glibc and gnulib's implementation guarantee this, but POSIX no

     longer requires it: http://austingroupbugs.net/view.php?id=185  */

  errno = 0;

  ASSERT (unsetenv (NULL) == -1);

  ASSERT (errno == EINVAL);

#endif

  return 0;

}