function testUpdateSubscriptionsFail()
 {
     $props = ['{http://calendarserver.org/ns/}source' => new \Sabre\DAV\Xml\Property\Href('http://example.org/cal.ics', false), '{DAV:}displayname' => 'cal', '{http://apple.com/ns/ical/}refreshrate' => 'P1W', '{http://apple.com/ns/ical/}calendar-color' => '#FF00FFFF', '{http://calendarserver.org/ns/}subscribed-strip-todos' => true, '{http://calendarserver.org/ns/}subscribed-strip-attachments' => true];
     $backend = new PDO($this->pdo);
     $backend->createSubscription('principals/user1', 'sub1', $props);
     $propPatch = new DAV\PropPatch(['{DAV:}displayname' => 'new displayname', '{http://calendarserver.org/ns/}source' => new \Sabre\DAV\Xml\Property\Href('http://example.org/cal2.ics', false), '{DAV:}unknown' => 'foo']);
     $backend->updateSubscription(1, $propPatch);
     $propPatch->commit();
     $this->assertEquals(['{DAV:}unknown' => 403, '{DAV:}displayname' => 424, '{http://calendarserver.org/ns/}source' => 424], $propPatch->getResult());
 }