tests/test-random.c

   1 /* Test random.
   2    Copyright (C) 2008-2020 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 #include <stdlib.h>
  20
  21 #include "signature.h"
  22 SIGNATURE_CHECK (srandom, void, (unsigned int));
  23 SIGNATURE_CHECK (initstate, char *, (unsigned int, char *, size_t));
  24 SIGNATURE_CHECK (setstate, char *, (char *));
  25 SIGNATURE_CHECK (random, long, (void));
  26
  27 #include <time.h>
  28
  29 #include "macros.h"
  30
  31 int
  32 main ()
  33 {
  34   char buf[128];
  35   unsigned int i;
  36   unsigned int n_big = 0;
  37
  38   initstate (time (NULL), buf, sizeof buf);
  39   for (i = 0; i < 1000; i++)
  40     {
  41       long r = random ();
  42       ASSERT (0 <= r);
  43       if (RAND_MAX / 2 < r)
  44         ++n_big;
  45     }
  46
  47   /* Fail if none of the numbers were larger than RAND_MAX / 2.  */
  48   return !n_big;
  49 }