使用testng{Page factory Model}执行多个类时出现空指针异常

Question

<suite name = "Adactin" verbose="1">
<parameter name="URL" value="http://www.adactin.com/HotelAppBuild2/"/>
<parameter name="PageTitle" value="AdactIn.com - Hotel Reservation System"/>
<test name = "RegressionTest">
<parameter name="Username" value="AdminSample"/>
<parameter name ="Password" value="AdminSample"/>
<classes>
<class name ="Tests.Test_HomePage"></class>
<class name="Tests.Test_HotelSelctPage"></class>
</classes>
</test>
</suite>

    `package Tests;

    import java.util.concurrent.TimeUnit;

    import org.openqa.selenium.By;
    import org.openqa.selenium.StaleElementReferenceException;
    import org.openqa.selenium.WebDriver;
    import org.openqa.selenium.firefox.FirefoxDriver;
    import org.openqa.selenium.support.ui.ExpectedConditions;
    import org.openqa.selenium.support.ui.WebDriverWait;
    import org.testng.Assert;
    import org.testng.annotations.BeforeSuite;
    import org.testng.annotations.BeforeTest;
    import org.testng.annotations.Parameters;
    import org.testng.annotations.Test;

    import PageFactory.HomePage;

    public class Test_HomePage 
{
     WebDriver driver;
     HomePage Obj;

  @BeforeSuite
  @Parameters({"URL","PageTitle"})
  public void setup(String URL,String PageTitle) 
  {
      driver= new FirefoxDriver();
      driver.get(URL);
      driver.manage().window().maximize();
      driver.manage().timeouts().implicitlyWait(5, TimeUnit.SECONDS);
      if(!(driver.getTitle().equalsIgnoreCase(PageTitle)))
      {
          Assert.fail("Home Page title is not as expected.Quitting the test..");
          driver.quit();
      }
      else
      {
          System.out.println(":: Home Page was displayed successfully ::");
          Obj=new HomePage(driver);
      }
  }

  @Test
  @Parameters({"Username","Password"})
  public void test_Login(String Username,String Password)
  {
      System.out.println("//Executing test_Login//");
    try 
    {
          Obj.LoginAction(Username, Password);

    } catch (NullPointerException e) 
    {
        System.out.println("exception details are : "+ e);
    }
      WebDriverWait wait=new WebDriverWait(driver,10);
      try
      {
          wait.until(ExpectedConditions.visibilityOfElementLocated(By.linkText("Logout")));
          if(!(driver.findElement(By.linkText("Logout")).isDisplayed()))
          {
              Assert.fail(":: Login is not successful.Logout button is not displayed ::");
              driver.quit();    
          }
          else
          {
              System.out.println(":: Login was successful ::");
             // driver.findElement(By.linkText("Logout")).click();
          }
        /*  if(!(driver.findElement(By.linkText("Click here to login again")).isDisplayed()))
          {
              Assert.fail(":: Logout was not successful ::");
              driver.quit();
          }     
          else
              System.out.println(":: Logout was successful ::");*/
      }   
      catch(StaleElementReferenceException e)
 {
    e.printStackTrace();  
    }
    /* finally
    {
    driver.quit();
    }*/
    }
    }`

package Tests;

import org.openqa.selenium.WebDriver;
import org.testng.annotations.Test;

import PageFactory.HotelSelct_Page;

public class Test_HotelSelctPage extends Test_HomePage
{
//  HotelSelct_Page obj;
    //WebDriver driver=null;

  @Test
  public void Dropdown() 
  {
//    obj= new HotelSelct_Page(driver);
    //obj.Select_Location();  
      System.out.println("hi");

  }
}

    [TestNG] Running:
      G:\Work\Selenium\Workspace\Adactin\src\TestNGDataFile.xml

    :: Home Page was displayed successfully ::
    //Executing test_Login//
    exception details are : java.lang.NullPointerException
    //Executing test_Login//
    :: Login was successful ::
    hi

    ===============================================
    Adactin
    Total tests run: 3, Failures: 1, Skips: 0
    ===============================================


Exception Trace:

java.lang.NullPointerException
    at com.google.common.base.Preconditions.checkNotNull(Preconditions.java:210)
    at org.openqa.selenium.support.ui.FluentWait.<init>(FluentWait.java:94)
    at org.openqa.selenium.support.ui.WebDriverWait.<init>(WebDriverWait.java:70)
    at org.openqa.selenium.support.ui.WebDriverWait.<init>(WebDriverWait.java:44)
    at Tests.Test_HomePage.test_Login(Test_HomePage.java:57)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:84)
    at org.testng.internal.Invoker.invokeMethod(Invoker.java:714)
    at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:901)
    at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1231)
    at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:127)
    at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:111)
    at org.testng.TestRunner.privateRun(TestRunner.java:767)
    at org.testng.TestRunner.run(TestRunner.java:617)
    at org.testng.SuiteRunner.runTest(SuiteRunner.java:334)
    at org.testng.SuiteRunner.runSequentially(SuiteRunner.java:329)
    at org.testng.SuiteRunner.privateRun(SuiteRunner.java:291)
    at org.testng.SuiteRunner.run(SuiteRunner.java:240)
    at org.testng.SuiteRunnerWorker.runSuite(SuiteRunnerWorker.java:52)
    at org.testng.SuiteRunnerWorker.run(SuiteRunnerWorker.java:86)
    at org.testng.TestNG.runSuitesSequentially(TestNG.java:1224)
    at org.testng.TestNG.runSuitesLocally(TestNG.java:1149)
    at org.testng.TestNG.run(TestNG.java:1057)
    at org.testng.remote.RemoteTestNG.run(RemoteTestNG.java:111)
    at org.testng.remote.RemoteTestNG.initAndRun(RemoteTestNG.java:204)
    at org.testng.remote.RemoteTestNG.main(RemoteTestNG.java:175)

package PageFactory;

import org.junit.Assert;
import org.openqa.selenium.By;
import org.openqa.selenium.StaleElementReferenceException;
import org.openqa.selenium.WebDriver;

public class HomePage 
{
    WebDriver driver;

    By Username=By.id("username");
    By Password=By.id("password");
    By Loginbutton=By.id("login");
    By ForgotPassword_Link=By.linkText("Forgot Password?");
    By NewUser_RegLink=By.linkText("New User Register Here");

    public HomePage(WebDriver driver)
    {
        this.driver=driver;
    }

    public void setUsername(String strUsername)
    {
        try
        {
            driver.findElement(Username).sendKeys(strUsername);
        }
        catch(StaleElementReferenceException e)
        {
            e.printStackTrace();
            Assert.fail();
        }
    }
    public void setPassword(String strPassword)
    {
        try 
        {
            driver.findElement(Password).sendKeys(strPassword);
        } 
        catch (StaleElementReferenceException e) 
        {
            e.printStackTrace();
            Assert.fail();
        }
    }
    public void clickLogin()
    {
        try 
        {
            driver.findElement(Loginbutton).click();
        } 
        catch (StaleElementReferenceException e) 
        {
            e.printStackTrace();
            Assert.fail();
        }
    }

    public void LoginAction(String strUsername,String strPassword)
    {
        this.setUsername(strUsername);
        this.setPassword(strPassword);
        this.clickLogin();
    }

}

第2页代码：

package PageFactory;

import java.util.ArrayList;
import java.util.List;

import org.openqa.selenium.By;
import org.openqa.selenium.StaleElementReferenceException;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.support.ui.Select;
import org.testng.annotations.Test;

public class HotelSelct_Page 
{
    WebDriver driver;
    By SearchHotel_Link     =By.linkText("Search Hotel");
    By BookedItenery_Link   =By.linkText("Booked Itinerary");
    By Change_PwdLink       =By.linkText("Change Password");
    By Logout_Link          =By.linkText("Logout");
    By Location_element     =By.xpath(".//*[@id='location']");
//  Select Location_DropDown=new Select(Location_element);
//  Select Hotel_DropDown   =new Select((WebElement) By.xpath(".//*[@id='hotels']"));
//Select Room_DropDown  =new Select((WebElement) By.xpath(".//*[@id='room_type']"));
//  Select NumberOfRooms_DropDown=new Select((WebElement) By.xpath(".//*[@id='room_nos']"));
    By CheckInDate_editBox  =By.id("datepick_in");
    By CheckOutDate_editBox =By.id("datepick_out");
//  Select Adults_DropDown  =new Select((WebElement) By.xpath(".//*[@id='adult_room']"));
//  Select Children_DropDown=new Select((WebElement) By.xpath(".//*[@id='child_room']"));
    By Search_Button        =By.id("Submit");
    By Reset_Button         =By.id("Reset");

    public HotelSelct_Page(WebDriver driver)
    {
        this.driver=driver;
    }

  public void Select_Location() 
  {
     /* WebElement Location_DropDown_Element =driver.findElement(Location_element);
      Select Location_DropDown = new Select(Location_DropDown_Element);
      Location_DropDown.selectByIndex(2);
      List<WebElement> Location_DropDownList = Location_DropDown.getOptions();
      for(WebElement s : Location_DropDownList)
          System.out.println(s.getText());*/
     // System.out.println("hi");
    /*  Select Loc_Dropdown = new Select(driver.findElement(Location_element));
      Loc_Dropdown.selectByIndex(2);
        */  
      //driver.findElement(Change_PwdLink).click();
      //System.out.println("hi");
  }
}

Answer 1

下面是您获得Nullpointer异常的原因。

>

您有两个testng测试方法，一个是“test_login”，另一个是“dropdown”

您将“test_homepage”类继承到“test_hotelselctpage”中，因此对于“test_hotelselctpage”类，您有两个testng方法，一个来自基类，另一个来自子类。所以总共有三种测试方法。

您的TestNg套件有一个测试，其中包含两个类。这意味着您有三个TestNg套件的方法。

当您运行testng套件时，它的运行方式如下：

首先开始执行类“test_hotelselctpage”作为“dropdown”方法在第一个线程中按字母顺序排在第一位。执行“setup”方法和初始化驱动程序对象，然后一个接一个地执行两个测试成功。