1 files changed, 61 insertions, 0 deletions
diff --git a/src/gl/tests/test-unsetenv.c b/src/gl/tests/test-unsetenv.c
new file mode 100644
index 0000000..e61fbbc
--- /dev/null
+++ b/src/gl/tests/test-unsetenv.c
@@ -0,0 +1,61 @@
+/* Tests of unsetenv.
+   Copyright (C) 2009-2021 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/>.  */
+
+/* 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;
+}