gistfile1.txt

class Foo < ActiveFedora::Base
  property :title, predicate: ::RDF::DC.title
  validates_presence_of :title
end

irb(main):006:0> f = Foo.new
=> #<Foo id: nil, title: []>
irb(main):007:0> f.valid?
=> false
irb(main):008:0> f.errors
=> #<ActiveModel::Errors:0x007fcdbe5b99b8 @base=#<Foo id: nil, title: []>, @messages={:title=>["can't be blank"]}>