require 'spec_helper'

describe Immutable::Deque do
  describe '#clear' do
    [
      [],
      ['A'],
      %w[A B C],
    ].each do |values|
      context "on #{values}" do
        let(:deque) { D[*values] }

        it 'preserves the original' do
          deque.clear
          deque.should eql(D[*values])
        end

        it 'returns an empty deque' do
          deque.clear.should equal(D.empty)
        end
      end
    end
  end

  context 'from a subclass' do
    it 'returns an instance of the subclass' do
      subclass = Class.new(Immutable::Deque)
      instance = subclass.new([1,2])
      instance.clear.should be_empty
      instance.clear.class.should be(subclass)
    end
  end
end