blah.rb

def group(cookies)
  return @group if @group

  current_set = set_size
  i = 0

  until @group
    if seed <= current_set
      @group = groups[i]
    else
      i += 1
      current_set += set_size
    end
  end

  @group
end


def set_size
  (1 / @groups.length.to_f)
end

def seed
  return @seed if @seed

  srand sha
  @seed = rand
end

def sha
  @sha ||= Digest::SHA1.hexdigest(test_name + ab_cookie_value.to_s).to_i(16)
end