require_relative '../../../spec_helper'

describe "Enumerator::Chain#rewind" do
  before(:each) do
    @obj = mock('obj')
    @obj.should_receive(:each).any_number_of_times.and_yield
    @second = mock('obj')
    @second.should_receive(:each).any_number_of_times.and_yield
    @enum = Enumerator::Chain.new(@obj, @second)
  end

  it "returns self" do
    @enum.rewind.should.equal? @enum
  end

  it "does nothing if receiver has not been iterated" do
    @obj.should_not_receive(:rewind)
    @obj.respond_to?(:rewind).should == true # sanity check
    @enum.rewind
  end

  it "does nothing on objects that don't respond_to rewind" do
    @obj.respond_to?(:rewind).should == false # sanity check
    @enum.each {}
    @enum.rewind
  end

  it "calls_rewind its objects" do
    @obj.should_receive(:rewind)
    @enum.each {}
    @enum.rewind
  end

  it "calls_rewind in reverse order" do
    @obj.should_not_receive(:rewind)
    @second.should_receive(:rewind).and_raise(RuntimeError)
    @enum.each {}
    -> { @enum.rewind }.should.raise(RuntimeError)
  end

  it "calls rewind only for objects that have actually been iterated on" do
    @obj = mock('obj')
    @obj.should_receive(:each).any_number_of_times.and_raise(RuntimeError)
    @enum = Enumerator::Chain.new(@obj, @second)

    @obj.should_receive(:rewind)
    @second.should_not_receive(:rewind)
    -> { @enum.each {} }.should.raise(RuntimeError)
    @enum.rewind
  end
end
