anchor.diff:      logical(c_bool), intent(inout) :: success
   
       call test_de_casteljau_one_round(success)
  +    call test_evaluate_barycentric(success)
   
     end subroutine surface_all_tests
   
  
positive.code: 
    end subroutine test_de_casteljau_one_round
  
  end module test_surface
  
negative.code: 
    use, intrinsic :: iso_c_binding, only: c_bool, c_double
    use surface, only: &
         de_casteljau_one_round, evaluate_barycentric
    use types, only: dp
    use unit_test_helpers, only: print_status, get_random_nodes
    implicit none
    private &
         test_de_casteljau_one_round, test_evaluate_barycentric
    public surface_all_tests
  
  contains
  