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    <h3>Editing: DOMNodeComparator.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php declare(strict_types=1);
/*
 * This file is part of sebastian/comparator.
 *
 * (c) Sebastian Bergmann &lt;sebastian@phpunit.de&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace SebastianBergmann\Comparator;

use function sprintf;
use function strtolower;
use DOMDocument;
use DOMNode;
use ValueError;

/**
 * Compares DOMNode instances for equality.
 */
class DOMNodeComparator extends ObjectComparator
{
    /**
     * Returns whether the comparator can compare two values.
     *
     * @param mixed $expected The first value to compare
     * @param mixed $actual   The second value to compare
     *
     * @return bool
     */
    public function accepts($expected, $actual)
    {
        return $expected instanceof DOMNode &amp;&amp; $actual instanceof DOMNode;
    }

    /**
     * Asserts that two values are equal.
     *
     * @param mixed $expected     First value to compare
     * @param mixed $actual       Second value to compare
     * @param float $delta        Allowed numerical distance between two values to consider them equal
     * @param bool  $canonicalize Arrays are sorted before comparison when set to true
     * @param bool  $ignoreCase   Case is ignored when set to true
     * @param array $processed    List of already processed elements (used to prevent infinite recursion)
     *
     * @throws ComparisonFailure
     */
    public function assertEquals($expected, $actual, $delta = 0.0, $canonicalize = false, $ignoreCase = false, array &amp;$processed = [])/*: void*/
    {
        $expectedAsString = $this-&gt;nodeToText($expected, true, $ignoreCase);
        $actualAsString   = $this-&gt;nodeToText($actual, true, $ignoreCase);

        if ($expectedAsString !== $actualAsString) {
            $type = $expected instanceof DOMDocument ? 'documents' : 'nodes';

            throw new ComparisonFailure(
                $expected,
                $actual,
                $expectedAsString,
                $actualAsString,
                false,
                sprintf(&quot;Failed asserting that two DOM %s are equal.\n&quot;, $type)
            );
        }
    }

    /**
     * Returns the normalized, whitespace-cleaned, and indented textual
     * representation of a DOMNode.
     */
    private function nodeToText(DOMNode $node, bool $canonicalize, bool $ignoreCase): string
    {
        if ($canonicalize) {
            $document = new DOMDocument;

            try {
                @$document-&gt;loadXML($node-&gt;C14N());
            } catch (ValueError $e) {
            }

            $node = $document;
        }

        $document = $node instanceof DOMDocument ? $node : $node-&gt;ownerDocument;

        $document-&gt;formatOutput = true;
        $document-&gt;normalizeDocument();

        $text = $node instanceof DOMDocument ? $node-&gt;saveXML() : $document-&gt;saveXML($node);

        return $ignoreCase ? strtolower($text) : $text;
    }
}
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