List of webelements getting cleared during my test run?

Question

I'm trying to compare two different tables using the method called VerifyOrderSummary located at the end of the main method below.

public static void main(String[] args) {

    // TODO Auto-generated method stub

    System.setProperty("webdriver.gecko.driver", "geckodriver.exe");
    driver = new FirefoxDriver();   

    driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

    Item testItem = Item.WRENCH;

    driver.get("http://test.url/WebOrderScreen");
    AddItem(testItem);
    ChangeItemQuantity(testItem, 3);

    WebElement shoppingCartListContents = driver.findElement(By.id("shopping-cart")).findElement(By.xpath(".//tbody[@class='nx-list-contents']"));
    List<WebElement> shoppingCartRows = shoppingCartListContents.findElements(By.tagName("tr"));

    System.out.println(shoppingCartRows.size());
    System.out.println(shoppingCartRows.get(0).getText());

    ClickWorkflowButton(Button.PAYMENTINFORMATION);

    WebElement orderSummaryListContents = driver.findElement(By.id("order-summary")).findElement(By.xpath(".//tbody[@class='nx-list-contents']"));
    List<WebElement> orderSummaryRows = orderSummaryListContents.findElements(By.tagName("tr"));

    VerifyOrderSummary(shoppingCartRows, orderSummaryRows);


}

The issue i am seeing is that when i print out the first row of shoppingRowCartsRows in the main method, it prints out correctly.

but within the VerifyOrderSummary method, it prints out a blank line:

 public static void VerifyOrderSummary(List<WebElement> shoppingCartRows, List<WebElement> orderSummaryRows) {      

    //given the shopping cart rows and order summary rows, compare the two

    for(int i = 0; i < shoppingCartRows.size(); i++) {

        System.out.println("shopping cart row: "+shoppingCartRows.get(i).getText());
        System.out.println("order summary row: "+orderSummaryRows.get(i).getText());


        //          Assert.assertEquals(shoppingCartRows.get(i).getText(), orderSummaryRows.get(i).getText());

        //System.out.println(models.get(i).getName());

    }

Can anyone tell me why that is happening? I'm completely lost at the moment.

Answer 1

I would not recommend to use WebElement objects as the carriers of some long-life information. They might change depending on the changes of your page. Instead I would recommend to have the following approach:

1. You have WebElement list that you have just populated somehow:

   List<WebElement> weList = driver.findElements(By.xpath("//some-x-path"));
   

2. Then you should create a list holding the types of valuable parts of your Webelements. For text it would look like:

   2.1. For Java 8:

   either

   List<String> weText = new ArrayList<>();
   weList.forEach(webElement -> {weText.add(webElement.getText());});
   

   or

   List<String> weText  = weList.stream().map(webElement -> webElement.getText()).collect(Collectors.toList());
   

   2.2. For pre-8 Java:

   List<String> weText = new ArrayList<>();
   for(WebElement webElement: weList){
       weText.add(webElement.getText());
   }
   

Now you can preserve the values for further comparison.