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

ruby_version_is "1.9" do
  describe "Enumerator#peek_values" do
    before(:each) do
      o = Object.new
      def o.each
        yield :a
        yield :b1, :b2
        yield :c
        yield :d1, :d2
        yield :e1, :e2, :e3
        yield nil
        yield
      end

      @e = o.to_enum
    end

    it "returns the next element in self" do
      @e.peek_values.should == [:a]
    end

    it "does not advance the position of the current element" do
      @e.next.should == :a
      @e.peek_values.should == [:b1, :b2]
      @e.next.should == [:b1, :b2]
    end

    it "can be called repeatedly without advancing the position of the current element" do
      @e.peek_values
      @e.peek_values
      @e.peek_values.should == [:a]
      @e.next.should == :a
    end

    it "works in concert with #rewind" do
      @e.next
      @e.next
      @e.rewind
      @e.peek_values.should == [:a]
    end

    it "returns an array with only nil if yield is called with nil" do
      5.times { @e.next }
      @e.peek_values.should == [nil]
    end

    it "returns an empty array if yield is called without arguments" do
      6.times { @e.next }
      @e.peek_values.should == []
    end

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