require 'spec_helper'

describe Immutable::List do
  describe '#transpose' do
    it 'takes a list of lists and returns a list of all the first elements, all the 2nd elements, and so on' do
      L[L[1, 'a'], L[2, 'b'], L[3, 'c']].transpose.should eql(L[L[1, 2, 3], L['a', 'b', 'c']])
      L[L[1, 2, 3], L['a', 'b', 'c']].transpose.should eql(L[L[1, 'a'], L[2, 'b'], L[3, 'c']])
      L[].transpose.should eql(L[])
      L[L[]].transpose.should eql(L[])
      L[L[], L[]].transpose.should eql(L[])
      L[L[0]].transpose.should eql(L[L[0]])
      L[L[0], L[1]].transpose.should eql(L[L[0, 1]])
    end

    it 'only goes as far as the shortest list' do
      L[L[1,2,3], L[2]].transpose.should eql(L[L[1,2]])
    end
  end
end