--- /dev/null
+/* Exercise mpz_probab_prime_p.
+
+Copyright 2002 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 3 of the License, or (at your
+option) any later version.
+
+The GNU MP Library 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 Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "tests.h"
+
+
+/* Enhancements:
+
+ - Test some big primes don't come back claimed to be composite.
+ - Test some big composites don't come back claimed to be certainly prime.
+ - Test some big composites with small factors are identified as certainly
+ composite. */
+
+
+/* return 1 if prime, 0 if composite */
+int
+isprime (long n)
+{
+ long i;
+
+ n = ABS(n);
+
+ if (n < 2)
+ return 0;
+ if (n == 2)
+ return 1;
+ if ((n & 1) == 0)
+ return 0;
+
+ for (i = 3; i < n; i++)
+ if ((n % i) == 0)
+ return 0;
+
+ return 1;
+}
+
+void
+check_one (mpz_srcptr n, int want)
+{
+ int got;
+
+ got = mpz_probab_prime_p (n, 25);
+
+ /* "definitely prime" is fine if we only wanted "probably prime" */
+ if (got == 2 && want == 1)
+ want = 2;
+
+ if (got != want)
+ {
+ printf ("mpz_probab_prime_p\n");
+ mpz_trace (" n ", n);
+ printf (" got =%d", got);
+ printf (" want=%d", want);
+ abort ();
+ }
+}
+
+void
+check_pn (mpz_ptr n, int want)
+{
+ check_one (n, want);
+ mpz_neg (n, n);
+ check_one (n, want);
+}
+
+/* expect certainty for small n */
+void
+check_small (void)
+{
+ mpz_t n;
+ long i;
+
+ mpz_init (n);
+
+ for (i = 0; i < 300; i++)
+ {
+ mpz_set_si (n, i);
+ check_pn (n, isprime (i));
+ }
+
+ mpz_clear (n);
+}
+
+int
+main (void)
+{
+ tests_start ();
+
+ check_small ();
+
+ tests_end ();
+ exit (0);
+}