public void find_date_time_within()
{
var today = DateTime.Today.ToLocal();
var from = today.Add(7.Hours());
var to = today.Add(31.Hours());
var period = new Period(from, to);
period.FindDateTime("0700").ShouldBe(today.Add(7.Hours()));
period.FindDateTime("0800").ShouldBe(today.Add(8.Hours()));
period.FindDateTime("2300").ShouldBe(today.Add(23.Hours()));
period.FindDateTime("0500").ShouldBe(today.Add(29.Hours())); // early morning the next day
period.FindDateTime("0300").ShouldBe(today.Add(27.Hours())); // early morning the next day
}