public void SerializerTreeVisitorVisitStringLiteralTest()
        {
            var            serializer = new JsonNodeWriter();
            TreeSerializer visitor    = new TreeSerializer(serializer);

            visitor.VisitStringLiteral(new StringLiteral(new Span(0, 10), "hello world"));
            Assert.AreEqual("\"StringLiteral\" : {\n  \"Span\" : {\n    \"start\" : \"0\",\n    \"end\" : \"10\"\n  },\n  \"Value\" : \"hello world\"\n}", serializer.ToString());
        }