acts_as_is_enabled.rb

module ActsAsIsEnabled
  extend ActiveSupport::Concern
  
  module ClassMethods
    def acts_as_is_enabled
      scope :enabled, where(:is_enabled => true)
      scope :disabled, where(:is_enabled => [false,nil]) # 如果 db 有設定 default => false 的話, 不用 nil 了, 看起來也會乾淨一點
    end
  end
  
  module InstanceMethods
    
    def disabled?
      !is_enabled
    end
    
    def enabled?
      is_enabled
    end
    
    def enable
      update_attributes :is_enabled => true
    end
    
    def disable
      update_attributes :is_enabled => false
    end
    
  end
  
end

acts_as_is_enabled_spec.rb

require 'spec_helper'

shared_examples_for "acts_as_enabled" do
  before do
    @klass = @instance_enabled.class
  end
  
  describe "scopes" do
    it "enabled" do
      @klass.enabled.include?(@instance_enabled).should be_true
      @klass.enabled.include?(@instance_disabled).should be_false
      @instance_disabled.enable
      @klass.enabled.include?(@instance_disabled).should be_true
    end

    it "disabled" do
      @klass.disabled.include?(@instance_disabled).should be_true
      @klass.disabled.include?(@instance_enabled).should be_false
      @instance_enabled.disable
      @klass.disabled.include?(@instance_enabled).should be_true
    end
  end
  
  describe "instances" do
    it "enable" do
      @instance_disabled.enabled?.should be_false
      @instance_disabled.disabled?.should be_true
      @instance_disabled.enable.should be_true
      @instance_disabled.enabled?.should be_true
      @instance_disabled.disabled?.should be_false
    end
    
    it "disable" do
      @instance_enabled.enabled?.should be_true
      @instance_enabled.disabled?.should be_false
      @instance_enabled.disable.should be_true
      @instance_enabled.enabled?.should be_false
      @instance_enabled.disabled?.should be_true
    end
  end
end


describe "all included class" do
  
  # 有 include 的 model class 都可以放這裡
  # Factory 裡面都要有 xxx_enabled 和 xxx_disabled
  [Pic, SpotPost].each do |klass| 
    describe klass do
      before do
        @instance_enabled = Factory "#{klass.to_s.underscore}"
        @instance_enabled.enable
        @instance_disabled = Factory "#{klass.to_s.underscore}"
        @instance_disabled.disable
      end
      it_should_behave_like "acts_as_enabled"
    end
  end

end