在 Selenium 中执行两个测试类时出现 NullPointer 异常答案

【问题标题】：NullPointer Exception while executing two test classes in Selenium在 Selenium 中执行两个测试类时出现 NullPointer 异常
【发布时间】：2020-10-23 20:22:55
【问题描述】：

我创建了两个测试类。登录测试类依赖于设置测试类。所以，我在登录测试中使用了dependsOnMethods 注释并扩展了设置类。但是在通过TestNG执行两个测试类时，设置测试执行成功，但在第二个测试类执行时出现空指针异常。

测试类单独执行良好。

第 1 类：设置代码

package com.selenium.tests;

import java.io.IOException;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.support.ui.Select;
import org.testng.annotations.AfterMethod;
import org.testng.annotations.AfterSuite;
import org.testng.annotations.AfterTest;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.BeforeSuite;
import org.testng.annotations.BeforeTest;
import org.testng.annotations.Test;

import com.selenium.pageObjects.SignIn;
import com.selenium.pageObjects.DashBoard;
import com.selenium.pageObjects.Setting;
import com.selenium.resources.base;

import junit.framework.Assert;

public class SettingTest extends base {

    public WebDriver driver;
    SignIn signIn;
    String getTitle;

    public static Logger log = LogManager.getLogger(SettingTest.class.getName());

    @BeforeTest
    public void intializeDriver() throws IOException {
        System.out.println("before Test");

        driver = browserIntilization();

        driver.get(prop.getProperty("Application_url"));
        log.info("Application is opened");
        
    }

    @Test
    public void Dealer_to_set_the_app_configuration() throws IOException, InterruptedException {
        System.out.println("1st Test");

        Setting sourceLogin = new Setting(driver);
        Select market = selectFunction(sourceLogin.getMarket());
        market.selectByVisibleText("USA");
        log.info("market is selected");

        Select language = selectFunction(sourceLogin.getlanguage());
        language.selectByVisibleText("English");

        log.info("Language is Selected");

        signIn = sourceLogin.getSignIn();
        Thread.sleep(5000);

         getTitle = signIn.getPageTitle();

        Assert.assertEquals("ICAR-X", getTitle);
        log.info("User redirected to Login Page Successfully.");

    }
    
    


    @AfterTest
    public void tearDown() {
        System.out.println("After Test Executed");
        driver.quit();

    }

}

第 2 类：登录代码

package com.selenium.tests;

import org.testng.annotations.Test;

import com.selenium.pageObjects.DashBoard;

import junit.framework.Assert;

public class LoginTest extends SettingTest{
    
    @Test (dependsOnMethods = ("Dealer_to_set_the_app_configuration"))
    public void Dealer_enters_valid_credential_to_login_inside_the_app() throws InterruptedException {
        System.out.println("2nd test");
        
        signIn.getDealerID("70052");
        log.info("DealerID is entered successfully");
        signIn.getUserID("x579303");
        log.info("userID is entered successfully");
        signIn.getPassword("Nissan#2020");
        log.info("password is entered successfully");
        DashBoard dashboard = signIn.getDashBoard();
        Thread.sleep(5000);
        dashboard.getPageTitle();
        Assert.assertEquals("ICAR-X", getTitle);
        log.info("User redirected to Dashboard Page Successfully.");
        
    }

}

错误

[RemoteTestNG] detected TestNG version 7.3.0
ERROR StatusLogger No Log4j 2 configuration file found. Using default configuration (logging only errors to the console), or user programmatically provided configurations. Set system property 'log4j2.debug' to show Log4j 2 internal initialization logging. See https://logging.apache.org/log4j/2.x/manual/configuration.html for instructions on how to configure Log4j 2
before Test
Starting ChromeDriver 85.0.4183.87 (cd6713ebf92fa1cacc0f1a598df280093af0c5d7-refs/branch-heads/4183@{#1689}) on port 40014
Only local connections are allowed.
Please see https://chromedriver.chromium.org/security-considerations for suggestions on keeping ChromeDriver safe.
ChromeDriver was started successfully.
[1602609611.367][WARNING]: This version of ChromeDriver has not been tested with Chrome version 86.
Oct 13, 2020 10:50:13 PM org.openqa.selenium.remote.ProtocolHandshake createSession
INFO: Detected dialect: W3C
1st Test
1st Test
After Test Executed
java.lang.NullPointerException
    at com.selenium.resources.base.getScreenShotPath(base.java:78)
    at com.selenium.listeners.Listeners.onTestFailure(Listeners.java:53)
    at org.testng.internal.TestListenerHelper.runTestListeners(TestListenerHelper.java:96)
    at org.testng.internal.TestInvoker.runTestResultListener(TestInvoker.java:220)
    at org.testng.internal.TestInvoker$MethodInvocationAgent.invoke(TestInvoker.java:832)
    at org.testng.internal.TestInvoker.invokeTestMethods(TestInvoker.java:147)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:146)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:128)
    at java.util.ArrayList.forEach(Unknown Source)
    at org.testng.TestRunner.privateRun(TestRunner.java:764)
    at org.testng.TestRunner.run(TestRunner.java:585)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:384)
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:378)
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:337)
    at org.testng.SuiteRunner.run(SuiteRunner.java:286)
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:53)
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:96)
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1218)
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1140)
    at org.testng.TestNG.runSuites(TestNG.java:1069)
    at org.testng.TestNG.run(TestNG.java:1037)
    at org.testng.remote.AbstractRemoteTestNG.run(AbstractRemoteTestNG.java:115)
    at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:251)
    at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:77)

基类代码

package com.selenium.resources;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Properties;
import java.util.concurrent.TimeUnit;

import org.apache.commons.io.FileUtils;
import org.openqa.selenium.OutputType;
import org.openqa.selenium.TakesScreenshot;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.safari.SafariDriver;
import org.openqa.selenium.support.ui.Select;
import org.testng.annotations.AfterSuite;
import org.testng.annotations.AfterTest;
import org.testng.annotations.BeforeSuite;
import org.testng.annotations.BeforeTest;

public class base {
    public WebDriver driver;
    public Properties prop;

    public WebDriver browserIntilization() throws IOException {

        prop = new Properties();
        FileInputStream fis = new FileInputStream(
                System.getProperty("user.dir") + "\\src\\test\\java\\com\\selenium\\resources\\properties.Properties");
        prop.load(fis);

        String browsername = prop.getProperty("browser");
        

        if (browsername.equals("safari")) {

            driver = new SafariDriver();

        } else if (browsername.equals("chrome")) {

            System.setProperty("webdriver.chrome.driver",
                    System.getProperty("user.dir") + "\\browser_Servers\\chromedriver.exe");
            driver = new ChromeDriver();

        } else if (browsername.equals("firefox")) {
            System.setProperty("webdriver.gecko.driver",
                    System.getProperty("user.dir") + "\\browser_Servers\\geckodriver.exe");
            driver = new FirefoxDriver();

        } else {
            System.setProperty("webdriver.ie.driver",
                    System.getProperty("user.dir") + "\\browser_Servers\\IEDriverServer.exe");
            driver = new FirefoxDriver();

        }

        driver.manage().window().maximize();
        driver.manage().timeouts().implicitlyWait(60, TimeUnit.SECONDS);

        return driver;

    }
    
    public  Select selectFunction(WebElement element) {
        
        Select select = new Select(element);
        
        return select;
        
    }
    
    public String getScreenShotPath(String testCaseName, WebDriver driver) throws IOException
    {
        TakesScreenshot ts=(TakesScreenshot) driver;
        File source =ts.getScreenshotAs(OutputType.FILE);
        String destinationFile = System.getProperty("user.dir")+"\\screenShots\\"+testCaseName+".png";
        FileUtils.copyFile(source,new File(destinationFile));
        return destinationFile;


    }
    
    
    
        

    
    
}

【问题讨论】：

你能提出你的基类代码吗？看起来空指针位于基类的 getScreenshotPatch 方法上。
我已经添加了基类代码。它单独运行良好，但在一起执行时遇到问题。
为什么要把驱动对象传给截图方法？驱动程序是从这个基类初始化的，它是公共的。尝试在此方法上向驱动程序对象添加空检查。我认为，浏览器可能已经关闭，但是您正在尝试截屏，在这种情况下驱动程序将为空。

标签： java selenium-webdriver testng

【解决方案1】：

请在此处发布您的 testng.xml，看来您的测试用例：设置代码 运行了 2 次，这是因为根据您共享的控制台输出，它显示 syso 消息“1st测试” 2 次，并且您在 @AfterTest 注释中使用了 driver.quit() ，那么您的 第二次测试 : Login Code won't run as driver.quit() 将终止浏览器的所有正在运行的会话。

快速解决方案：Testng.xml

<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd" >

<suite name="AsPerNeed">

    <test name="Setting code">
        <classes>
            <class name="package.class 1" />
            
        </classes>
    </test>

    <test name="Login code`">  
        <classes>
            <class name="package.class 2" />
            
        </classes>
    </test>
    
</suite>

从您的第一个测试类中删除@AfterTest 注释，并在您的基类中删除用户@AfterSuit 注释，如下所示。

@AfterSuite
    public void tearDown() {
        driver.quit();

    }

【讨论】：