public void TestAddSec()
{
ResetTime();
_time.AddSec(6);
Assert.AreEqual("00:00:06,000", _time.ToString());
_time.AddSec(60);
Assert.AreEqual("00:01:06,000", _time.ToString());
_time.AddSec(3600);
Assert.AreEqual("01:01:06,000", _time.ToString());
}