public void Test_CalculateVolocity() { //arrange DateTime oldDateTime = DateTime.ParseExact("20151006213456789", "yyyyMMddHHmmssfff", CultureInfo.InvariantCulture); DateTime newDateTime = DateTime.ParseExact("20151006213459789", "yyyyMMddHHmmssfff", CultureInfo.InvariantCulture); //act double velocity = _uut.CalculateVolocity(5, 10, 4, 6, oldDateTime, newDateTime); //assert Assert.That(velocity, Is.EqualTo(1.7950549357115013438)); }