@Test
public void existing_head_used_if_present() throws Exception
{
Document document = new Document(new XMLMarkupModel());
document.newRootElement("html").element("head").comment("existing head").getParent()
.element("body").text("body content");
DocumentLinkerImpl linker = new DocumentLinkerImpl(true, false, true, "1.2.3");
linker.addStylesheetLink("foo.css", null);