public void is_valid_test()
{
var cron_schedule = new CronSchedule();
Assert.IsTrue(cron_schedule.isValid("*/2"));
Assert.IsTrue(cron_schedule.isValid("* * * * *"));
Assert.IsTrue(cron_schedule.isValid("0 * * * *"));
Assert.IsTrue(cron_schedule.isValid("0,1,2 * * * *"));
Assert.IsTrue(cron_schedule.isValid("*/2 * * * *"));
Assert.IsTrue(cron_schedule.isValid("1-4 * * * *"));
Assert.IsTrue(cron_schedule.isValid("1-55/3 * * * *"));
Assert.IsTrue(cron_schedule.isValid("1,10,20 * * * *"));
Assert.IsTrue(cron_schedule.isValid("* 1,10,20 * * *"));
}