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，我得到了两次失败和一次成功。我不知道为什么。对于其中两个状态，end_time_before_final 方法中的 return if end_time.blank? 语句在每次都应该为 false 时评估为 true。 “推迟”是唯一似乎通过的状态。知道这里可能会发生什么吗？

Answer 1

您似乎遇到了documentation 中提到的警告：

这里有一个重要的警告是，由于 ActiveModel 验证的限制 框架，自定义验证器在定义运行时将无法按预期工作 在多个州。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 验证只会运行 对于 :second_gear 状态。为避免这种情况，您可以定义您的 像这样的自定义验证：

 class Vehicle
   include ActiveModel::Validations

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