public function testUnknownClassWhileSavingBecauseOfVersion3()
{
$doc = new XmlDocument('2.2.0');
$doc->loadFromString('
<div>
<bdo dir="rtl">I am reversed!</bdo>
</div>');
// This should fail because in QTI 2.2.0 because <bdo> does not exist.
$doc->setVersion('2.1.0');
$expectedMsg = "'bdo' components are not supported in QTI version '2.1.0'";
$this->setExpectedException('qtism\\data\\storage\\xml\\XmlStorageException', $expectedMsg, XmlStorageException::VERSION);
$str = $doc->saveToString(true);
}