状态机,模型验证和RSpec

Question

这是我当前的类定义和规范:

class Event < ActiveRecord::Base

  # ...

  state_machine :initial => :not_started do

    event :game_started do
      transition :not_started => :in_progress
    end

    event :game_ended do
      transition :in_progress => :final
    end

    event :game_postponed do
      transition [:not_started, :in_progress] => :postponed
    end

    state :not_started, :in_progress, :postponed do
      validate :end_time_before_final
    end
  end

  def end_time_before_final
    return if end_time.blank?
    errors.add :end_time, "must be nil until event is final" if end_time.present?
  end

end

describe Event do
  context 'not started, in progress or postponed' do
    describe '.end_time_before_final' do
      ['not_started', 'in_progress', 'postponed'].each do |state|
        it 'should not allow end_time to be present' do
          event = Event.new(state: state, end_time: Time.now.utc)
          event.valid?
          event.errors[:end_time].size.should == 1
          event.errors[:end_time].should == ['must be nil until event is final']
        end
      end
    end
  end
end

当我运行规范时,我得到两次失败并取得一次成功.我不知道为什么.对于其中两个状态,方法中的return if end_time.blank?语句在end_time_before_final每次都应为false时求值为true.'推迟'是唯一似乎通过的州.想知道这里可能会发生什么吗？

Answer 1

您似乎遇到了文档中提到的警告:

这里有一个重要的警告是,由于ActiveModel的验证框架中存在约束,当定义为在多个状态下运行时,自定义验证器将无法按预期工作.例如:

 class Vehicle
   include ActiveModel::Validations

   state_machine do
     ...
     state :first_gear, :second_gear do
       validate :speed_is_legal
     end
   end
 end

在这种情况下,:speed_is_legal验证仅针对:second_gear状态运行.为避免这种情况,您可以像这样定义自定义验证:

 class Vehicle
   include ActiveModel::Validations

   state_machine do
     ...
     state :first_gear, :second_gear do
       validate {|vehicle| vehicle.speed_is_legal}
     end
   end
 end