require 'spec_helper'

describe Immutable::List do
  describe '#drop' do
    it 'is lazy' do
      -> { Immutable.stream { fail }.drop(1) }.should_not raise_error
    end

    [
      [[], 10, []],
      [['A'], 10, []],
      [['A'], -1, ['A']],
      [%w[A B C], 0, %w[A B C]],
      [%w[A B C], 2, ['C']],
    ].each do |values, number, expected|
      context "with #{number} from #{values.inspect}" do
        let(:list) { L[*values] }

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

        it "returns #{expected.inspect}" do
          list.drop(number).should == L[*expected]
        end
      end
    end
  end
end