Dates/arithmetic Error During Test. Expression: t1 .+ (Dates.Month(1) + Dates.Day(1)) == [Dates.Date(2009, 2, 2) Dates.Date(2009, 2, 3) Dates.Date(2009, 2, 4); Dates.Date(2009, 3, 2) Dates.Date(2009, 3, 3) Dates.Date(2009, 3, 4)]