我写了以下测试。看起来 htmlunit mouseOver() 函数不起作用（我没有看到弹出框的 html 代码）。我错过了什么吗？我该如何解决这个问题？
@Test
public void test() throws Exception {
try {
WebClient client = new WebClient(BrowserVersion.FIREFOX_3_6);
HtmlPage currentPage = client.getPage("http://plugins.learningjquery.com/cluetip/demo/");
String xpath = "//a[@title='jTip Style!']";
HtmlElement elm = (HtmlElement) currentPage.getByXPath(xpath).get(0);
xpath = "(//img[@src='kids-drop-sand.jpg'])[1]";
HtmlPage newPage = (HtmlPage) elm.mouseOver();
Assert.assertTrue(newPage.getByXPath(xpath).size() > 0, "Popover is not displayed");
} catch (Exception ex) {
logger.error("Exception thrown in " + this.getClass().toString()
+ " " + ex.getMessage(), ex);
throw ex;
}
}