//TODO need some comfortable way to enable/check the PDF version
//assertEquals("%PDF-1.5", doc.getDocument().getHeaderString());
//assertEquals("1.5", catalog.getVersion());
PDPage page = (PDPage)catalog.getAllPages().get(0);
PDPropertyList props = page.findResources().getProperties();
assertNotNull(props);
PDOptionalContentGroup ocg = props.getOptionalContentGroup(COSName.getPDFName("MC0"));
assertNotNull(ocg);
assertEquals("overlay", ocg.getName());