Fixing creating empty nodes for all PHP 'false' values. Closes #14.

classes/CFPropertyList/CFType.php

@@ -71,7 +71,7 @@ public function setValue($value) {
   public function toXML(DOMDocument $doc, $nodeName) {
     $node = $doc->createElement($nodeName);
 
-    if($this->value != '') {
+    if($this->value !== '') {
       $text = $doc->createTextNode($this->value);
       $node->appendChild($text);
     }

tests/EmptyElementsTest.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace CFPropertyList;
+
+error_reporting(E_ALL | E_STRICT);
+ini_set('display_errors', 'on');
+
+if (!defined('LIBDIR')) {
+    define('LIBDIR', __DIR__ . '/../classes/CFPropertyList');
+}
+
+require_once(LIBDIR . '/CFPropertyList.php');
+
+class EmptyElementsTest extends \PHPUnit_Framework_TestCase {
+    public function testWriteFile() {
+        $expected = '<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0"><dict><key>string</key><string/><key>number</key><integer>0</integer><key>double</key><real>0</real></dict></plist>
+';
+
+        $plist = new CFPropertyList();
+        $dict = new CFDictionary();
+
+        $dict->add('string', new CFString(''));
+        $dict->add('number', new CFNumber(0));
+        $dict->add('double', new CFNumber(0.0));
+
+        $plist->add($dict);
+        $this->assertEquals($expected, $plist->toXML());
+    }
+}