这次利用 zTree 异步加载的Demo做测试，同时分别利用 WebElement 的 click 方法 和 zTree 的 expandNode 方法展开节点，进行异步加载。使用起来并不困难，直接看代码即可。 

package lesson4;

import static org.junit.Assert.*;

import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import org.openqa.selenium.JavascriptExecutor;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.support.ui.ExpectedCondition;
import org.openqa.selenium.support.ui.WebDriverWait;

public class ExampleForAjax  {
 
    static WebDriver driver;
    
    @BeforeClass
    public static void init() {
    	System.out.println("init...");
    	// 如果你的 FireFox 没有安装在默认目录，那么必须在程序中设置
    	System.setProperty("webdriver.firefox.bin", "D:\\Program Files\\Mozilla Firefox\\firefox.exe");
    	// 创建一个 FireFox 的浏览器实例
    	driver = new FirefoxDriver();
    }
 
    @Test
    public void test() {
    	// 让浏览器访问 zTree Demo
    	driver.get("http://www.ztree.me/v3/demo/cn/core/async.html");
    
    	// 等待 zTree 初始化完毕，Timeout 设置10秒
    	try {
    		(new WebDriverWait(driver, 10, 500)).until(new ExpectedCondition<Boolean>() {
    			public Boolean apply(WebDriver d) {
    				WebElement element = (WebElement) ((JavascriptExecutor)driver).executeScript("return $('#treeDemo li').get(0);");
    				return element != null;
    			}
    		});
    
    	} catch(Exception e) {
    		e.printStackTrace();
    	}
    
    	((JavascriptExecutor)driver).executeScript("window.zTreeObj = $.fn.zTree.getZTreeObj('treeDemo');");
    
    	//判断节点总数
    	Long count =(Long) ((JavascriptExecutor)driver).executeScript("return window.zTreeObj.transformToArray(window.zTreeObj.getNodes()).length;");
    	assertTrue(count == 4);
    
    	//利用 expandNode 方法展开第一个父节点
    	((JavascriptExecutor)driver).executeScript("window.zTreeNode = window.zTreeObj.getNodeByParam('isParent', true); window.zTreeObj.expandNode(window.zTreeNode, true);");
    	try {
    		(new WebDriverWait(driver, 10, 500)).until(new ExpectedCondition<Boolean>() {
    			public Boolean apply(WebDriver d) {
    				Boolean isAjaxing = (Boolean) ((JavascriptExecutor)driver).executeScript("return !!window.zTreeNode.isAjaxing;");
    				return !isAjaxing;
    			}
    		});
    
    	} catch(Exception e) {
    		e.printStackTrace();
    	}
    	//判断节点总数
    	count =(Long) ((JavascriptExecutor)driver).executeScript("return window.zTreeObj.transformToArray(window.zTreeObj.getNodes()).length;");
    	assertTrue(count == 8);
    
    	//模拟 click 事件 单击节点 +/- 号展开
    	WebElement element = (WebElement) ((JavascriptExecutor)driver).executeScript("window.zTreeNode = window.zTreeNode.children[0]; return $('#' + window.zTreeNode.tId + '_switch').get(0);");
    	element.click();
    
    	// 展开第一个子节点
    	((JavascriptExecutor)driver).executeScript("window.zTreeObj.expandNode(window.zTreeNode, true);");
    	try {
    		(new WebDriverWait(driver, 10, 500)).until(new ExpectedCondition<Boolean>() {
    			public Boolean apply(WebDriver d) {
    				Boolean isAjaxing = (Boolean) ((JavascriptExecutor)driver).executeScript("return !!window.zTreeNode.isAjaxing;");
    				return !isAjaxing;
    			}
    		});
    
    	} catch(Exception e) {
    		e.printStackTrace();
    	}
    	//判断节点总数
    	count =(Long) ((JavascriptExecutor)driver).executeScript("return window.zTreeObj.transformToArray(window.zTreeObj.getNodes()).length;");
    	assertTrue(count == 12);
    
    }
    
    @AfterClass
    public static void destory() {
    	System.out.println("destory...");
    	//关闭浏览器
    	driver.quit();
    }
}

package lesson4;

import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import org.openqa.selenium.JavascriptExecutor;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.support.ui.ExpectedCondition;
import org.openqa.selenium.support.ui.WebDriverWait;

public class ExampleForIframe  {
 
    static WebDriver driver;
    
    @BeforeClass
    public static void init() {
    	System.out.println("init...");
    	// 如果你的 FireFox 没有安装在默认目录，那么必须在程序中设置
    	System.setProperty("webdriver.firefox.bin", "D:\\Program Files\\Mozilla Firefox\\firefox.exe");
    	// 创建一个 FireFox 的浏览器实例
    	driver = new FirefoxDriver();
    }
 
    @Test
    public void test() {
    	// 让浏览器访问 zTree Demo
    	driver.get("http://www.ztree.me/v3/demo.php#_102");
    
    	// 等待 iframe 加载完毕，Timeout 设置10秒
    	try {
    		(new WebDriverWait(driver, 10, 500)).until(new ExpectedCondition<Boolean>() {
    			public Boolean apply(WebDriver d) {
    				Boolean loaded = (Boolean) ((JavascriptExecutor)driver).executeScript("return !!demoIframe.$.fn.zTree.getZTreeObj('treeDemo');");
    				return loaded;
    			}
    		});
    
    	} catch(Exception e) {
    		e.printStackTrace();
    	}
    
    	((JavascriptExecutor)driver).executeScript("demoIframe.zTreeObj = demoIframe.$.fn.zTree.getZTreeObj('treeDemo');");
    
    	//利用 expandNode 方法展开第2个根节点
    	((JavascriptExecutor)driver).executeScript("demoIframe.zTreeNode = demoIframe.zTreeObj.getNodes()[1]; demoIframe.zTreeObj.expandNode(demoIframe.zTreeNode, true);");
    
    	// 等待 5 秒
    	try {
    		(new WebDriverWait(driver, 5, 1000)).until(new ExpectedCondition<Boolean>() {
    			public Boolean apply(WebDriver d) {
    				return false;
    			}
    		});
    
    	} catch(Exception e) {}
    
    }
    
    @AfterClass
    public static void destory() {
    	System.out.println("destory...");
    	//关闭浏览器
    	driver.quit();
    }
}