Works in the browser but could not make it work in the operation test, anyone spots the issue?

contract&op&test.rb

# contract
property :logo, skip_if: :all_blank, 
                prepopulator: ->(options) { self.logo = Image.new },
                populator: ->(fragment, model, options) { model || self.logo = Image.new } do
  property :_destroy, virtual: true
  property :data
end

# models 
#challenge.rb
has_one :logo, as: :imageable, class_name: 'Image', dependent: :destroy
 
#image.rb // using carrierwave
class Image < ActiveRecord::Base
  belongs_to :imageable, polymorphic: true

  # file uploader
  mount_uploader :data, AttachmentUploader  
end

#test    
it 'with a logo' do
  res, op = Challenge::Create.run(challenge: {name: 'Heineken World Challenge', 
                                              introduction: 'Introduction for Heineken challenge',
                                              logo: { data: File.open("#{Rails.root}/test/support/images/barbara.png") } },
                                              current_user: user)


  res.must_equal true
  op.model.name.must_equal 'Heineken World Challenge'
  op.model.introduction.must_equal 'Introduction for Heineken challenge'
  op.model.user.must_equal user    
  op.model.logo.must_be_instance_of Image 
  #-------- FAILS HERE --------
  #valid params#test_0001_with a logo [****/test/concepts/challenge/create_test.rb:29]:
  #Expected nil to be an instance of Image, not NilClass.
end