[perl5.git] / t / op / srand.t

#!./perl -w

# Test srand.

use strict;
use Test::More tests => 3;

# Generate a load of random numbers.
# int() avoids possible floating point error.
sub mk_rand { map int rand 10000, 1..100; }


# Check that rand() is deterministic.
srand(1138);
my @first_run  = mk_rand;

srand(1138);
my @second_run = mk_rand;

ok( eq_array(\@first_run, \@second_run),  'srand(), same arg, same rands' );


# Check that different seeds provide different random numbers
srand(31337);
@first_run  = mk_rand;

srand(1138);
@second_run = mk_rand;

ok( !eq_array(\@first_run, \@second_run),
                                 'srand(), different arg, different rands' );


# This test checks whether Perl called srand for you.
@first_run  = `$^X -le "print int rand 100 for 1..100"`;
@second_run = `$^X -le "print int rand 100 for 1..100"`;

ok( !eq_array(\@first_run, \@second_run), 'srand() called automatically');
Commit	Line	Data
efec44ca AB	1	#!./perl -w
	2
	3	# Test srand.
	4
	5	use strict;
4d300a87	6	use Test::More tests => 3;
efec44ca AB	7
	8	# Generate a load of random numbers.
	9	# int() avoids possible floating point error.
	10	sub mk_rand { map int rand 10000, 1..100; }
	11
	12
	13	# Check that rand() is deterministic.
	14	srand(1138);
	15	my @first_run = mk_rand;
	16
	17	srand(1138);
	18	my @second_run = mk_rand;
	19
	20	ok( eq_array(\@first_run, \@second_run), 'srand(), same arg, same rands' );
	21
	22
	23	# Check that different seeds provide different random numbers
	24	srand(31337);
	25	@first_run = mk_rand;
	26
	27	srand(1138);
	28	@second_run = mk_rand;
	29
	30	ok( !eq_array(\@first_run, \@second_run),
	31	'srand(), different arg, different rands' );
	32
	33
efec44ca AB	34	# This test checks whether Perl called srand for you.
	35	@first_run = `$^X -le "print int rand 100 for 1..100"`;
	36	@second_run = `$^X -le "print int rand 100 for 1..100"`;
	37
	38	ok( !eq_array(\@first_run, \@second_run), 'srand() called automatically');