require 'spec_helper'

describe Immutable::List do
  describe '#intersperse' do
    it 'is lazy' do
      -> { Immutable.stream { fail }.intersperse('') }.should_not raise_error
    end

    [
      [[], []],
      [['A'], ['A']],
      [%w[A B C], ['A', '|', 'B', '|', 'C']]
    ].each do |values, expected|
      context "on #{values.inspect}" do
        let(:list) { L[*values] }

        it 'preserves the original' do
          list.intersperse('|')
          list.should eql(L[*values])
        end

        it "returns #{expected.inspect}" do
          list.intersperse('|').should eql(L[*expected])
        end
      end
    end
  end
end