How Can I render a Markup Container?

We have some test code but the wicket test fails, because it can not render the MarkUp Container in a html file. Is the any command to let wicket do this?

@Test public void testRendering() {

    FragenAntwortenUebersichtPage page = new FragenAntwortenUebersichtPage();
        tester.startPage(page);
        tester.assertRenderedPage(FragenAntwortenUebersichtPage.class);

}