require 'spec_helper'

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

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

        context 'with a block' do
          it 'preserves the original' do
            list.drop_while { |item| item < 'C' }
            list.should eql(L[*values])
          end

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

        context 'without a block' do
          it 'returns an Enumerator' do
            list.drop_while.class.should be(Enumerator)
            list.drop_while.each { false }.should eql(list)
            list.drop_while.each { true  }.should be_empty
          end
        end
      end
    end
  end
end