ruby-on-rails - 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，我遇到了两次失败和一次成功。我不知道为什么。对于其中两种状态，end_time_before_final 方法中的 return if end_time.blank? 语句每次都应为 false 时计算结果为 true。 “推迟”是唯一似乎通过的状态。知道这里会发生什么吗？

Answer 1

您似乎遇到了 documentation 中提到的警告:

One important caveat here is that, due to a constraint in ActiveModel's validation framework, custom validators will not work as expected when defined to run in multiple states. For example:

 class Vehicle
   include ActiveModel::Validations

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

In this case, the :speed_is_legal validation will only get run for the :second_gear state. To avoid this, you can define your custom validation like so:

 class Vehicle
   include ActiveModel::Validations

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