QTextDocument::setHtml hangs up with provided html

int main(int argc, char *argv[])
{
    QGuiApplication a(argc, argv);
    QTextDocument doc;    QFile file("test.html");
    file.open(QIODevice::ReadOnly);    QByteArray data = file.readAll();
    file.close();    
    doc.setHtml(data);    //here takes forever
    return a.exec();
}