ruby self trick - learning aid for the jr devs

gistfile1.txt

require "forwardable"

class Items
  include Enumerable
  extend Forwardable

  def_delegators :@all, :each,    :map,     :inject,
                        :reduce,  :select,  :reject

  attr_reader :all, :filtered

  def initialize(items=[])
    @filtered = @all = items.flatten
  end

  def filter(opts)
    @filtered ||= opts.map {|k,v| 
      @all.select {|item| item.send(k) == v }
    }.flatten
    self
  end

  def <<(*item)
    @all = [@all + [item]].flatten
  end

  def to_a
   @all.to_a.flatten || @filtered.to_a.flatten
  end
end

require 'ostruct'
class Item < OpenStruct
end

require 'minitest/autorun'

describe Items do
  subject { Items }
  let(:items) {[
      Item.new(name: "awesome", group: "agroup" ),
      Item.new(name: "cooler",  group: "agroup")
    ]}

  it "must accept an array in the initializer" do
    assert subject.new([])
  end

  it "must allow enumeration" do
    subject.new(items).each_with_index do |item, i|
      item.must_equal items[i]
    end
  end

  describe "#filter" do
    subject { Items.new(items) }

    it "it filters the results in #filtered" do
      subject.filter(
        { name: "awesome" }
      ).filtered[0].name.must_equal "awesome"
    end

  end
end