specific_type_spec.rb

class Credentials
  @@credentials = {}
  class << self
    def set_current(credentials)
      @@credentials[Thread.current.object_id] = credentials
    end
    def current
      @@credentials[Thread.current.object_id]
    end
  end
end

class Session
  def initialize(credentials)
    @credentails = credentials
  end
end

class SpecificType
  @@starting_from = {}
  @@session = {}

  class << self
    delegate :each, :first, to: :to_a

    def from(nr)
      @@starting_from[Thread.current.object_id] = nr
      self
    end

    def to_a
      session
      result = 3.times.to_a.map { |e| e+= @@starting_from[Thread.current.object_id].to_i }
      result
    end

    def all
      clear_current_scope
      self
    end

    def clear_current_scope
      @@starting_from.delete Thread.current.object_id
    end

    def session
      @@session[Thread.current.object_id] ||= Session.new(Credentials.current)
    end
  end
end

describe SpecificType do
  before do
    Credentials.set_current(api_key: 'a', login: 'l', password: 'p')
  end
  it 'handles chaining and clears state before different invocations' do
    SpecificType.all.from(2).each do |val|
      p val
    end
    puts "-"*20
    SpecificType.all.each do |val|
      p val
    end
    puts "-"*20
    p SpecificType.all.first
  end
end