public void Initialization_WithResultSelector ()
    {
      var parseInfo = CreateParseInfo ();
      var node = new AggregateFromSeedExpressionNode (parseInfo, _seed, _func, _resultSelector);

      Assert.That (node.Source, Is.SameAs (SourceNode));
      Assert.That (node.Seed, Is.SameAs (_seed));
      Assert.That (node.Func, Is.SameAs (_func));
      Assert.That (node.OptionalResultSelector, Is.SameAs (_resultSelector));
    }
    public override void SetUp ()
    {
      base.SetUp ();
      _seed = Expression.Constant (0);
      _func = ExpressionHelper.CreateLambdaExpression<int, int, int> ((total, i) => total + i);
      _resultSelector = ExpressionHelper.CreateLambdaExpression<int, string> (total => total.ToString());

      _nodeWithoutResultSelector = new AggregateFromSeedExpressionNode (CreateParseInfo (), _seed, _func, null);
      _nodeWithResultSelector = new AggregateFromSeedExpressionNode (CreateParseInfo (), _seed, _func, _resultSelector);
    }