tempname: Add tests.

* tests/test-tempname.c: New file.
* modules/tempname-tests: New file.

1 files changed, 57 insertions, 0 deletions

diff --git a/tests/test-tempname.c b/tests/test-tempname.c
new file mode 100644
index 0000000000..d463eec2b4
--- /dev/null
+++ b/tests/test-tempname.c
@@ -0,0 +1,57 @@
+/* Test of creating a temporary file.
+   Copyright (C) 2022 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 Bruno Haible <bruno@clisp.org>, 2022.  */
+
+#include <config.h>
+
+#include "tempname.h"
+
+#include <string.h>
+#include <unistd.h>
+
+#include "macros.h"
+
+int
+main ()
+{
+  /* Verify that two consecutive calls to gen_tempname return two different
+     file names, with a high probability.  */
+  const char *templ18 = "gl-temp-XXXXXX.xyz";
+  char filename1[18 + 1];
+  char filename2[18 + 1];
+
+  strcpy (filename1, templ18);
+  int fd1 = gen_tempname (filename1, strlen (".xyz"), 0, GT_FILE);
+  ASSERT (fd1 >= 0);
+
+  strcpy (filename2, templ18);
+  int fd2 = gen_tempname (filename2, strlen (".xyz"), 0, GT_FILE);
+  ASSERT (fd2 >= 0);
+
+  /* With 6 'X' and a good pseudo-random number generator behind the scenes,
+     the probability of getting the same file name twice in a row should be
+     1/62^6 < 1/10^10.  */
+  ASSERT (strcmp (filename1, filename2) != 0);
+
+  /* Clean up.  */
+  close (fd1);
+  close (fd2);
+  unlink (filename1);
+  unlink (filename2);
+
+  return 0;
+}