ruby-on-rails – 测试：在anaf中的reject_if

class User < ActiveRecord::Base
  has_many :languages,:dependent => :destroy
  accepts_nested_attributes_for :languages,:reject_if => lambda { |l| l[:name].blank? }
end

我想用RSpec 2.0.0测试reject_if部分.目前我有两个简单的测试用例

it "should not save language without name by accepts_nested_attributes" do
    lambda {
      @user.update_attributes!("languages_attributes"=>{"0"=>{}})
    }.should_not change(Language,:count)
  end

  it "should save language with name by accepts_nested_attributes" do
    lambda {
      @user.update_attributes!("languages_attributes"=>{"0"=>{"name"=>"lang_name"}})
    }.should change(Language,:count).by(1)
  end

但是我对测试很新,看起来很奇怪.
我想知道这是否是测试reject_if的正确方法？有没有更好的方法呢？