Ruby-on-rails – Dependent factories in Factory Girl

I have 2 factories. Beta_user and Beta_invite. Basically before a Beta_user can validly save I have to create an entry of Beta_invite. Unfortunately these models don't have clean associations, but they do share an email field.

Factory.sequence :email do |n|
  "email#{n}@factory.com"
end

#BetaInvite
Factory.define :beta_invite do |f|
  f.email {Factory.next(:email)}
  f.approved false
  f.source "web"
end

#User
Factory.define :user do |f|
  f.email {Factory.next(:email)}
  f.password "password"
end


#User => BetaUser
Factory.define :beta_user, :parent => :user do |f|
  f.after_build do |user|
    if BetaInvite.find_by_email(user.email).nil?
      Factory(:beta_invite, :email => user.email)
    end
  end
end

So in the beta beta_user factory I am trying to use the after_build call back to create the beta_invite factory.

However it seems to be acting async or something. Possibly doing the find_by_email fetch?

If I try this:

Factory(:beta_user)
Factory(:beta_user)
Factory(:beta_user)

I get a failure stating that there is no record of a beta_invite with that users email.

If instead I try:

Factory.build(:beta_user).save
Factory.build(:beta_user).save
Factory.build(:beta_user).save

I get better results. As if calling the .build method and waiting to save allows time for the beta_invite factory to be created. Instead of calling Factory.create directly. The docs say that in the case of calling Factory.create both the after_build and after_create callbacks get called.

Any help is much appreciated.

UPDATE:

So the User model I am using does a before_validation call to the method that checks if there is a beta invite. If I move this method call to before_save instead. It works correctly. Is there something i'm over looking. When does factory_girl run the after_build and after_create callbacks in relation to active-record's before_validation and before_save?