module RSpec::Mocks::VerifyingDouble

def respond_to?(message, include_private=false)
  return super unless null_object?
  method_ref = __mock_proxy.method_reference[message]
  case method_ref.visibility
  when :public    then true
  when :private   then include_private
  when :protected then include_private || RUBY_VERSION.to_f < 2.0
  else !method_ref.unimplemented?
  end
end