public function issue17()
{
vfsStreamWrapper::register();
vfsStreamWrapper::setRoot(new vfsStreamDirectory('root', 0770));
vfsStreamWrapper::getRoot()->chgrp(vfsStream::GROUP_USER_1)->chown(vfsStream::OWNER_USER_1);
$this->assertFalse(mkdir(vfsStream::url('root/doesNotWork')));
$this->assertFalse(vfsStreamWrapper::getRoot()->hasChild('doesNotWork'));
}