ESMF_RunTestBackwards Subroutine

      subroutine ESMF_RunTestBackwards(testType, YYl, MM, DD, Dl, cal)

! !ARGUMENTS:
      integer, intent(in) :: testType
      integer(ESMF_KIND_I8), intent(inout) :: YYl
      integer, intent(inout) :: MM
      integer, intent(inout) :: DD
      integer(ESMF_KIND_I8), intent(inout) :: Dl
      type(ESMF_Calendar), intent(inout) :: cal
        
! !DESCRIPTION:
!     Goes backwards one day at a time until the calendar conversion 
!     algorithm breaks.
!
!EOPI
      logical :: broken 

      broken = .false.
      do while (.not.broken)
    
        ! calculate what previous Julian Day number should be
        Dl = Dl - 1

        ! calculate what the previous date in given calendar should be
        DD = DD - 1
        if (DD.eq.0) then
          MM = MM - 1
          if (MM.eq.0) then
            MM = 12
            YYl = YYl - 1
          end if
          DD = DaysPerMonth(MM)
          ! check if leap year
          if (MM.eq.2) then
            if (ESMF_IsLeapYear(YYl, cal)) then
              DD = 29
            end if
          end if
        end if

        ! check calculated dates against ESMF dates
        broken = ESMF_CheckTime(testType, YYl, MM, DD, Dl, cal, rc)
      end do

      end subroutine ESMF_RunTestBackwards