MDL-38829 core: Unit test for xmlize using two sample xml files.

The file sample_questions.xml from moodle-stack is properly formed.
The file sample_questions_wrong.xml has mismatching tags.
Comparison is performed with recursive array comparison.
Error messages and returned data structures are compared.
Call with: phpunit lib/tests/xmlize_test.php

lib/tests/xmlize_test.php

@@ -0,0 +1,274 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Test xmlize xml import.
+ *
+ * @package    core
+ * @category   phpunit
+ * @copyright  2017 Kilian Singer {@link http://quantumtechnology.info}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+global $CFG;
+require_once($CFG->libdir . '/xmlize.php');
+
+/**
+ * xmlize.php - xmlize() is by Hans Anderson, {@link http://www.hansanderson.com/contact/}
+ *
+ * Ye Ole "Feel Free To Use it However" License [PHP, BSD, GPL].
+ * some code in xml_depth is based on code written by other PHPers
+ * as well as one Perl script.  Poor programming practice and organization
+ * on my part is to blame for the credit these people aren't receiving.
+ * None of the code was copyrighted, though.
+ *
+ * @package core
+ * @subpackage lib
+ * @author Hans Anderson
+ * @version This is a stable release, 1.0.  I don't foresee any changes, but you
+ * might check {@link http://www.hansanderson.com/php/xml/} to see
+ * @copyright Hans Anderson
+ * @license Feel Free To Use it However
+ */
+
+/**
+ * Create an array structure from an XML string.
+ *
+ * Usage:<br>
+ * <code>
+ * $xml = xmlize($array);
+ * </code>
+ * See the function {@link traverse_xmlize()} for information about the
+ * structure of the array, it's much easier to explain by showing you.
+ * Be aware that the array is somewhat tricky.  I use xmlize all the time,
+ * but still need to use {@link traverse_xmlize()} quite often to show me the structure!
+ *
+ * THIS IS A PHP 5 VERSION:
+ *
+ * This modified version basically has a new optional parameter
+ * to specify an OUTPUT encoding. If not specified, it defaults to UTF-8.
+ * I recommend you to read this PHP bug. There you can see how PHP4, PHP5.0.0
+ * and PHP5.0.2 will handle this.
+ * {@link http://bugs.php.net/bug.php?id=29711}
+ * Ciao, Eloy :-)
+ *
+ * @param string $data The XML source to parse.
+ * @param int $whitespace  If set to 1 allows the parser to skip "space" characters in xml document. Default is 1
+ * @param string $encoding Specify an OUTPUT encoding. If not specified, it defaults to UTF-8.
+ * @param bool $reporterrors if set to true, then a {@link xml_format_exception}
+ *      exception will be thrown if the XML is not well-formed. Otherwise errors are ignored.
+ * @return array representation of the parsed XML.
+ */
+function xmlize_old($data, $whitespace = 1, $encoding = 'UTF-8', $reporterrors = false) {
+
+    $data = trim($data);
+    $vals = array();
+    $parser = xml_parser_create($encoding);
+    xml_parser_set_option($parser, XML_OPTION_CASE_FOLDING, 0);
+    xml_parser_set_option($parser, XML_OPTION_SKIP_WHITE, $whitespace);
+    xml_parse_into_struct($parser, $data, $vals);
+
+    // Error handling when the xml file is not well-formed
+    if ($reporterrors) {
+        $errorcode = xml_get_error_code($parser);
+        if ($errorcode) {
+            $exception = new xml_format_exception(xml_error_string($errorcode),
+                    xml_get_current_line_number($parser),
+                    xml_get_current_column_number($parser));
+            xml_parser_free($parser);
+            throw $exception;
+        }
+    }
+    xml_parser_free($parser);
+
+    $i = 0;
+    if (empty($vals)) {
+        // XML file is invalid or empty, return false
+        return false;
+    }
+
+    $array = array();
+    $tagname = $vals[$i]['tag'];
+    if (isset($vals[$i]['attributes'])) {
+        $array[$tagname]['@'] = $vals[$i]['attributes'];
+    } else {
+        $array[$tagname]['@'] = array();
+    }
+
+    $array[$tagname]["#"] = xml_depth($vals, $i);
+
+    return $array;
+}
+
+/**
+ * @internal You don't need to do anything with this function, it's called by
+ * xmlize. It's a recursive function, calling itself as it goes deeper
+ * into the xml levels.  If you make any improvements, please let me know.
+ * @access private
+ */
+function xml_depth($vals, &$i) {
+    $children = array();
+
+    if ( isset($vals[$i]['value']) )
+    {
+        array_push($children, $vals[$i]['value']);
+    }
+
+    while (++$i < count($vals)) {
+
+        switch ($vals[$i]['type']) {
+
+           case 'open':
+
+                if ( isset ( $vals[$i]['tag'] ) )
+                {
+                    $tagname = $vals[$i]['tag'];
+                } else {
+                    $tagname = '';
+                }
+
+                if ( isset ( $children[$tagname] ) )
+                {
+                    $size = sizeof($children[$tagname]);
+                } else {
+                    $size = 0;
+                }
+
+                if ( isset ( $vals[$i]['attributes'] ) ) {
+                    $children[$tagname][$size]['@'] = $vals[$i]["attributes"];
+
+                }
+
+                $children[$tagname][$size]['#'] = xml_depth($vals, $i);
+
+            break;
+
+
+            case 'cdata':
+                array_push($children, $vals[$i]['value']);
+            break;
+
+            case 'complete':
+                $tagname = $vals[$i]['tag'];
+
+                if( isset ($children[$tagname]) )
+                {
+                    $size = sizeof($children[$tagname]);
+                } else {
+                    $size = 0;
+                }
+
+                if( isset ( $vals[$i]['value'] ) )
+                {
+                    $children[$tagname][$size]["#"] = $vals[$i]['value'];
+                } else {
+                    $children[$tagname][$size]["#"] = '';
+                }
+
+                if ( isset ($vals[$i]['attributes']) ) {
+                    $children[$tagname][$size]['@']
+                                             = $vals[$i]['attributes'];
+                }
+
+            break;
+
+            case 'close':
+                return $children;
+            break;
+        }
+
+    }
+
+        return $children;
+
+
+}
+/**
+ * This function performs a recursive array comparison.
+ *
+ * Code from {@link https://stackoverflow.com/questions/3876435/recursive-array-diff}.
+ *
+ * @package    core
+ * @category   phpunit
+ */
+function arrayRecursiveDiff($aArray1, $aArray2) {
+    $aReturn = array();
+    foreach ($aArray1 as $mKey => $mValue) {
+        if (array_key_exists($mKey, $aArray2)) {
+            if (is_array($mValue)) {
+                $aRecursiveDiff = arrayRecursiveDiff($mValue, $aArray2[$mKey]);
+                if (count($aRecursiveDiff)) {
+                    $aReturn[$mKey] = $aRecursiveDiff;
+                }
+            } else {
+                if ($mValue != $aArray2[$mKey]) {
+                    $aReturn[$mKey] = $mValue;
+                }
+           }
+       } else {
+           $aReturn[$mKey] = $mValue;
+       }
+    }
+    return $aReturn;
+}
+
+/**
+ * This test compares library against the original xmlize XML importer.
+ *
+ * @package    core
+ * @category   phpunit
+ * @copyright  2017 Kilian Singer {@link http://quantumtechnology.info}
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class core_xmlize_testcase extends basic_testcase {
+    public function test_xmlimport_of_proper_file() {
+        global $CFG;
+        $filecontent = file_get_contents($CFG->libdir . "/tests/sample_questions.xml");
+        // Put in the next line a modified file to see that it detects any difference.
+        $filecontent2 = file_get_contents($CFG->libdir . "/tests/sample_questions.xml");
+        $xml_new = xmlize($filecontent);
+        $xml_old = xmlize_old($filecontent2);
+        $diff = arrayRecursiveDiff($xml_old, $xml_new);
+        $this->assertSame($diff, array());
+    }
+    public function test_xmlimport_of_wrong_file() {
+        global $CFG;
+        $filecontent = file_get_contents($CFG->libdir . "/tests/sample_questions_wrong.xml");
+        // Put in the next line a modified file to see that it detects any difference.
+        $filecontent2 = file_get_contents($CFG->libdir . "/tests/sample_questions_wrong.xml");
+        $msg1="";
+        $msg2="";
+        $xml_new = array();
+        $xml_old = array();
+        try {
+            $xml_new = xmlize($filecontent, 1, "UTF-8", true);
+        } catch (Exception $e) {
+            $msg1 = $e->getMessage();
+            // echo 'Exception caught on purpose: ', $msg1, "\n";
+        }
+        try {
+            $xml_old = xmlize_old($filecontent2, 1, "UTF-8", true);
+        } catch (Exception $e) {
+            $msg2 = $e->getMessage();
+            // echo 'Exception caught on purpose: ', $msg2, "\n";
+        }
+        $diff = arrayRecursiveDiff($xml_old, $xml_new);
+        $this->assertSame($diff, array());
+        $this->assertSame($msg1, $msg2);
+    }
+}