generic array adapter

gistfile1.rb

class ArrayAdapter
  def initialize(array, &block)
    raise 'Adapter is useless without a block' unless block_given?
    @raw = array
    @transformer = block
  end

  def each(&block)
    # StackOverflow
    # http://stackoverflow.com/q/27798855/253098

    @raw.map { |raw| @transformer.call(raw) }.each(&block)
  end
end

describe '#each' do
  it 'applies transformation block' do
    old = [1, 2, 3]
    adapted = ArrayAdapter.new old do |v|
      v.to_s
    end
    adapted.each do |v|
      expect(v).to be_kind_of String
    end
  end
end