public function testGetUsers()
 {
     $query = \OC_DB::prepare('SELECT DISTINCT `userid` FROM `*PREFIX*preferences`');
     $result = $query->execute();
     $expected = array();
     while ($row = $result->fetchRow()) {
         $expected[] = $row['userid'];
     }
     $this->assertEquals($expected, \OC_Preferences::getUsers());
 }