public function test_hex_string()
{
$count = 2000;
$tolerance = 0.6;
$buckets = array_combine(str_split('0123456789abcdef'), array_fill(0, 16, 0));
for ($i = 1; $i <= $count; $i++) {
$len = mt_rand(2, 256);
$str = PHPRandom::getHexString($len);
$this->assertEquals($len, strlen($str));
$this->assertEquals(true, isset($buckets[$str[0]]));
$buckets[$str[0]]++;
}
$distribution = 0;
foreach ($buckets as $key => $value) {
if ($value > $count / 16 * 0.5) {
$distribution++;
}
if ($value < $count / 16 * 1.5) {
$distribution++;
}
}
$this->assertGreaterThan(16, $distribution);
}
<?
include_once "../config.php";
$gift = "WATER";
for ($i=0; $i < 20;$i++)
{
$serial = PHPRandom::getHexString("12");
$query = "INSERT INTO serial_info_(serial_code,gift) values('".$serial."','".$gift."')";
$result = mysqli_query($my_db, $query);
}
?>
