Check for string format.

node_format.js

var libxml = require('libxml');

module.exports.to_string = function(assert) {
    var doc1_string = [
      '<?xml version="1.0" encoding="UTF-8"?>',
      '<root><child to="wongfoo"/></root>',
    ].join("\n");

    var expected_string = "<child/>";

    var doc1 = libxml.parseXmlString(doc1_string);
    var node = doc1.child(0).node('child');
    require('util').print(node + "\n");
    require('util').print(require('util').format.apply(console, [node]) + "\n");
    console.log(node);
    assert.equal(node.toString(), expected_string);
    assert.done();
}