CarbonFitness.BusinessLogic.UnitHistory.Line.GetPreviousValuePoint C# (CSharp) Метод

        public ValuePoint GetPreviousValuePoint(DateTime date)
        {
            if (date <= GetFirstDate()) {
                return null;
            }
            return valuePoints.Where(x => x.Date < date).OrderByDescending(x => x.Date).First();
        }

 public void ShouldGetPreviousKeyValue()
 {
     var historyValues = new Line(getTestValues());
     var h = historyValues.GetPreviousValuePoint(DateTime.Today.AddDays(-1));
     Assert.That(h.Date, Is.EqualTo(DateTime.Today.AddDays(-2)));
 }