Rails 3 Validations - Association Properties, RSpec, and Factory Girl - ruby-on-rails

Question

I'm trying to write a validation class in rails 3 that will check for the presence of at least one associated object that has a particular property value.
In my scenario, an Account can have many Users. The User model has a "Role" string field. An account must have at least one User with a Role that equals "admin".
The following code is breaking during my testing (I'm using rspec & Factory Girl). When the tests are executed, the account_id is returning as null.
Here is the model:
class Account < ActiveRecord::Base
validates :name, :presence => true, :uniqueness => true
validate :has_one_admin
has_many :users
attr_accessible :name
private
def has_one_admin
User.where(:role => "admin", :account_id => self.id).count > 0
end
end
Here is the error being thrown by rspec:
Error message being thrown: Failure/Error: #account = Factory(:account_with_admin)
ActiveRecord::StatementInvalid:
SQLite3::SQLException: no such column: users.account_id: SELECT COUNT(*) FROM "users" WHERE "users"."role" = 'admin' AND "users"."account_id" IS NULL
Here is the RSpec test:
require 'spec_helper'
describe Team do
# - Removed -
# before(:each) do
# #account = Factory(:account)
# #attr = { :name => "Testing Team"}
# end
# Modified after discussion...
before(:each) do
#user = Factory(:user)
#act_attr = { :name => "My Account",
:users => #user }
#account = Account.new(#act_attr)
#attr = { :name => "Testing Team"}
end
# End of modification
it "must have a name" do
no_name_team = Team.new(#attr.merge(:name => ""))
no_name_team.should_not be_valid
end ...
And finally, my factory file:
Factory.define :admin, :class => User do |f|
f.email 'admin#admin.com'
f.password 'password'
f.role 'admin'
end
Factory.define :team, :class => Team do |f|
f.name 'Testing Team'
end
Factory.define :account, :class => Account do |f|
f.name 'Testing Account'
end
Factory.define :account_with_admin, :parent => :account do |f|
f.after_create { |a| Factory(:admin, :account => a) }
end
My assumption is that I'm jumping ahead of the persisting of the object somewhere but I'm just not sure where. Thanks for any help / direction!