public function testAddCustomGroupMultipleItemFieldWithItemInterface()
{
$feed = $this->manager->get('article');
$feed->add(new FakeItemInterfaceEntity());
$feed->addItemField(new GroupItemField('author', [new ItemField('name', 'getFeedItemAuthorName', ['cdata' => true]), new ItemField('email', 'getFeedItemAuthorEmail')]));
$output = $feed->render('rss');
$this->assertContains(<<<'EOF'
<author>
<name><![CDATA[John Doe]]></name>
<email>[email protected]</email>
</author>
EOF
, $output);
}