public void AverageSpread()
 {
     var agentTwo = new Agent { Name = "Two" };
     var agentThree = new Agent { Name = "Three" };
     var agentFiller = new Agent { Name = "Filler" };
     var agents = new List<Agent> {agentTwo ,agentThree, agentFiller  };
     var schedule = new Schedule(agents, DateTime.Now, DateTime.Now.AddDays(5));
     schedule.AssignPrimary(schedule[0], agentTwo);
     schedule.AssignPrimary(schedule[1], agentThree);
     schedule.AssignPrimary(schedule[2], agentTwo);
     schedule.AssignPrimary(schedule[3], agentFiller);
     schedule.AssignPrimary(schedule[4], agentThree);
     Assert.AreEqual((decimal)2.5, schedule.AverageSpread);
 }