require 'spec_helper'

describe Immutable::List do
  describe '#subsequences' do
    let(:list) { L[1,2,3,4,5] }

    it 'yields all sublists with 1 or more consecutive items' do
      result = []
      list.subsequences { |l| result << l }
      result.size.should == (5 + 4 + 3 + 2 + 1)
      result.sort.should == [[1], [1,2], [1,2,3], [1,2,3,4], [1,2,3,4,5],
        [2], [2,3], [2,3,4], [2,3,4,5], [3], [3,4], [3,4,5], [4], [4,5], [5]]
    end

    context 'with no block' do
      it 'returns an Enumerator' do
        list.subsequences.class.should be(Enumerator)
        list.subsequences.to_a.sort.should == [[1], [1,2], [1,2,3], [1,2,3,4], [1,2,3,4,5],
        [2], [2,3], [2,3,4], [2,3,4,5], [3], [3,4], [3,4,5], [4], [4,5], [5]]
      end
    end
  end
end
