public void TimePeriod_Diff(byte h1, byte m1, byte s1,
byte h2, byte m2, byte s2,
byte h3, byte m3, byte s3)
{
TimePeriod tp1 = new TimePeriod(h1, m1, s1);
TimePeriod tp2 = new TimePeriod(h2, m2, s2);
TimePeriod tpExpected = new TimePeriod(h3, m3, s3);
Assert.AreEqual(tp1.Difference(tp2), tpExpected);
}