我正在运行4并行使用 testNG 还有 selenium 。我的java文件如下所示：

public class SecondNGTest {

    public static WebDriver driver;
    public static ChromeOptions chromeOptions;

    public static final String USERNAME = PRIVATE";
    public static final String AUTOMATE_KEY = "PRIVATE";
    public static final String URL = "https://" + USERNAME + ":" + AUTOMATE_KEY + "@hub-cloud.browserstack.com/wd/hub";

    public static DesiredCapabilities caps;

    @Test    
    public void executSessionOne() throws MalformedURLException{
            //First session of WebDriver
        caps = new DesiredCapabilities();
        caps.setCapability("os", "Windows");
        caps.setCapability("os_version", "10");
        caps.setCapability("browser", "Chrome");
        caps.setCapability("browser_version", "80.0 beta");
        caps.setCapability("browserstack.local", "false");
        caps.setCapability("browserstack.selenium_version", "3.5.2");

        caps.setCapability("name", "selenium test");

        driver = new RemoteWebDriver(new URL(URL), caps);
        chromeOptions = new ChromeOptions();

        String chromeDriverPath = "resources/chromedriver.exe";
        System.setProperty("webdriver.chrome.driver", chromeDriverPath);   
            //Goto guru99 site
            driver.get("http://google.com/");

        }

    @Test    
        public void executeSessionTwo() throws MalformedURLException{
            //Second session of WebDriver
        caps = new DesiredCapabilities();
        caps.setCapability("os", "Windows");
        caps.setCapability("os_version", "10");
        caps.setCapability("browser", "Chrome");
        caps.setCapability("browser_version", "80.0 beta");
        caps.setCapability("browserstack.local", "false");
        caps.setCapability("browserstack.selenium_version", "3.5.2");

        caps.setCapability("name", "selenium test");

        driver = new RemoteWebDriver(new URL(URL), caps);
        chromeOptions = new ChromeOptions();

        String chromeDriverPath = "resources/chromedriver.exe";
        System.setProperty("webdriver.chrome.driver", chromeDriverPath);   
            //Goto guru99 site
            driver.get("http://youtube.com/");

        }

    @Test    
        public void executSessionThree() throws MalformedURLException{
            //Third session of WebDriver
        caps = new DesiredCapabilities();
        caps.setCapability("os", "Windows");
        caps.setCapability("os_version", "10");
        caps.setCapability("browser", "Chrome");
        caps.setCapability("browser_version", "80.0 beta");
        caps.setCapability("browserstack.local", "false");
        caps.setCapability("browserstack.selenium_version", "3.5.2");

        caps.setCapability("name", "selenium test");

        driver = new RemoteWebDriver(new URL(URL), caps);
        chromeOptions = new ChromeOptions();

        String chromeDriverPath = "resources/chromedriver.exe";
        System.setProperty("webdriver.chrome.driver", chromeDriverPath);   
            //Goto guru99 site
            driver.get("http://slack.com/");

        }    

    @Test    
    public void executSessionFour() throws MalformedURLException{
        //Third session of WebDriver
    caps = new DesiredCapabilities();
    caps.setCapability("os", "Windows");
    caps.setCapability("os_version", "10");
    caps.setCapability("browser", "Chrome");
    caps.setCapability("browser_version", "80.0 beta");
    caps.setCapability("browserstack.local", "false");
    caps.setCapability("browserstack.selenium_version", "3.5.2");

    caps.setCapability("name", "selenium test");

    driver = new RemoteWebDriver(new URL(URL), caps);
    chromeOptions = new ChromeOptions();

    String chromeDriverPath = "resources/chromedriver.exe";
    System.setProperty("webdriver.chrome.driver", chromeDriverPath);   
        //Goto guru99 site
        driver.get("http://yahoo.com/");

    } 

    @AfterTest
    public void browserclose (){
        driver.quit();
        System.out.println("TestCase : Browser was closed");
    }
}

它的工作原理是一次打开4个浏览器窗口并运行测试，但问题是它们永远不会结束。这个 @AfterTest 块只被触发一次，所以其中一个窗口确实关闭了，但其余的窗口仍然打开，我必须手动关闭它们。每次测试完成后，如何关闭/退出每个驱动程序？
编辑：这是我的testng.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE suite SYSTEM "https://testng.org/testng-1.0.dtd" >
<suite name="TestSuite"  >
<test name="testGuru" thread-count="4" parallel="methods">
<classes>
<class name="selerixautomation.SecondNGTest">
</class>
</classes>
</test>
</suite>