title: FactoryGirl, has_one association and validation failed
body: <p>These are 2 simple models:</p>
  
  <pre><code>class Post &lt; ActiveRecord::Base
    has_one :asset, :dependent =&gt; :destroy
  
    validates :asset, presence: true
  end
  
  class Asset &lt; ActiveRecord::Base
    belongs_to :post
  end
  </code></pre>
  
  <p>I'm trying to create a factory like this:</p>
  
  <pre><code>  factory :post do
      # fields...
  
      asset { FactoryGirl.create(:asset) }
    end
  
    factory :asset do
      # fields...
  
      post
    end
  </code></pre>
  
  <p>But, running the spec it enters a loop.</p>
  
  <p>I've also tryied this:</p>
  
  <pre><code>  factory :post do
      # fields...
  
      before(:create) do |post, evaluator|
        FactoryGirl.create_list(:asset, 1, post: post)
      end
    end
  </code></pre>
  
  <p>But ended up in "Validation failed: Asset can't be blank".</p>
  
  <p>How do I represent my situation?</p>