<?xml version="1.0" encoding="UTF-8"?>
<XML ID="XMLEquipment">
    <Equipment Action="U">
        <Notes>This & that</Notes>
    </Equipment>
</XML>

$dom = new DOMDocument;
$dom->load($filename);
$val = (new DOMXPath($dom))->query("//XML/Equipment/Notes")->item(0)->nodeValue;
$this->assertEquals("This & that", $val);