require File.expand_path('../../../spec_helper', __FILE__)

ruby_version_is "1.9" do
  describe "Enumerator#peek" do
    before(:each) do
      @e = (1..5).to_a.to_enum
    end

    it "returns the next element in self" do
      @e.peek.should == 1
    end

    it "does not advance the position of the current element" do
      @e.next.should == 1
      @e.peek.should == 2
      @e.next.should == 2
    end

    it "can be called repeatedly without advancing the position of the current element" do
      @e.peek
      @e.peek
      @e.peek.should == 1
      @e.next.should == 1
    end

    it "works in concert with #rewind" do
      @e.next
      @e.next
      @e.rewind
      @e.peek.should == 1
    end

    it "raises StopIteration if called on a finished enumerator" do
      5.times { @e.next }
      lambda { @e.peek }.should raise_error(StopIteration)
    end
  end
end
