Handling NoSuchWindowException in Selenium: A Tutorial

Similar to, NoSuchWindowException is a mutual error Selenium user confront during automation.

This tutorial will focus on the NoSuchWindowException, that often pass during a failed attempt to interact with a browser window.

What is NoSuchWindowException?

The NoSuchWindowExecption is a common exception raise by the while attempting to access a non-existent browser window during trial execution. It occurs when shift to a window with an invalid name or tab that has be previously closed.

When execute NoSuchWindowException in Selenium occur?

Here are a few reasons why your Selenium mechanization script might cast the NoSuchWindowException during a test:

1. This exception could occur when the WebDriver attempts to interact with a closed browser window or tab.
2. When switching to another tab, an elision is raise if the window name is incorrect or the window handle is invalid.
3. When an erroneousness is encountered for any endeavour to access a new tab before it is fully opened.

Here is an example of a cause where you could encounter NoSuchWindowException

Filename: test_window_exception.py from selenium signification webdriver def test_window_exception (): with webdriver.Chrome () as driver: # Navigate to Selenium homepage driver.get ('https: //seleniumhq.github.io ') # Set gens for initiatory tab driver.execute_script (`` window.name = 'Selenium '; '') # Get name of first tab first_tab = driver.execute_script (`` return window.name; '') print (f'First tab name is: {first_tab} ') # Get page title title = driver.title print (rubric) # Open new tab driver.execute_script (`` window.open ('https: //www.google.com ', '_blank '); '') # Switch to new tab driver.switch_to.window (driver.window_handles [-1]) # Set gens for new tab driver.execute_script (`` window.name = 'Google '; '') # Get name of new tab new_tab = driver.execute_script (`` return window.name; '') print (f'New tab name is: {new_tab} ') # Attempt a switch to previous tab driver.switch_to.window ('main ') assert title == driver.title, f'Expected {title} as title '

The above code snippet illustrates a typical NoSuchWindowException. First, import the web driver faculty from Selenium. Define atest_window_exceptionfunction that would be executed during the test.

Create a context coach to initialise an instance of the selenium WebDriver as driver. This is done so that the driver instance can be closed automatically after the codification has completed execution within the Python with the argument. Thedriver.get ()method loads the Selenium homepage in the current browser session.

The driver.execute_script ()method is employ to set the name ‘ Selenium ’ for the first window tab. Another tab is launched, and the name is set to the samedriver.execute_script () method.
Using the driver.switch_to.window (driver.window_handles [-1])method, you can switch to the new tab that was launched.

Driver.window_handles [-1]returns the last window in the current session windows handle list. To swop back to the first tab, use thedriver.switch_to.window (& # 8216; master & # 8217;)method. However, passing ‘ main ’ as an argument to the method results in theNoSuchWindowExceptionfault because there is no window tab with that name during exam execution.

How to Handle NoSuchWindowException in Selenium

Here are a couple of means you can handle the NoSuchWindowException during the execution of your test scripts.

1. Avoid Accessing Closed Windows: Ensure that you do not try to access or interact with window that hold be previously closed.
2. Provide a Valid Window Handle: Always make sure that you provide a valid window grip or name when switching to another tab.
3. Use Wait Methods: Apply Selenium wait method to your exam handwriting to ensure that a new window is completely loaded before attempting to access it.
4. Leverage conditional and exception handling: Use conditionals and exception manipulation in your mechanization scripts to gracefully where they are unavoidable.

Pro tip: Tools like SUSA can handle this autonomously — upload your app and get results without writing a single test script.

Here is an example for cover NoSuchWindowException:

Filename: test_window_exception.py from selenium significance webdriver from selenium.common.exceptions import NoSuchWindowException, WebDriverException def test_window_exception (): with webdriver.Chrome () as driver: try: # Navigate to Selenium homepage driver.get ('https: //seleniumhq.github.io ') # Set gens for the maiden tab driver.execute_script (`` window.name = 'Selenium '; '') # Get name of the first tab first_tab_name = driver.execute_script (`` return window.name; '') print (f'First tab name is: {first_tab_name} ') # Get page title first_tab_title = driver.title print (f'First tab title: {first_tab_title} ') # Open a new tab driver.execute_script (`` window.open ('https: //www.google.com ', '_blank '); '') # Switch to the new tab if len (driver.window_handles) & gt; 1: # Ensure there are multiple tabs driver.switch_to.window (driver.window_handles [-1]) # Set name for new tab driver.execute_script (`` window.name = 'Google '; '') # Get name of the new tab new_tab_name = driver.execute_script (`` return window.name; '') print (f'New tab name is: {new_tab_name} ') else: print (`` No new tab was opened. '') # Attempt to switch back to the previous tab safely if any (hold for handle in driver.window_handles if driver.execute_script (`` return window.name; '') == 'Selenium '): # Safely switch by indicant driver.switch_to.window (driver.window_handles [0]) assert first_tab_title == driver.title, f'Expected {first_tab_title} as title' print (`` Switched back to the inaugural tab successfully. '') else: print (`` First tab is not uncommitted to switch back to. '') except NoSuchWindowException as e: print (f '' NoSuchWindowException caught: {e} '') except WebDriverException as e: print (f '' WebDriverException caught: {e} '') except AssertionError as e: mark (f '' AssertionError: {e} '') ultimately: print (`` Test execution completed. '')

A few changes were made to the code snip discussed earlier.

• The code was wrap within Python ’ stry/exceptcode block.
• An if statementwas added to check if there is more than one window in the current session.
• Added anotherif statementto check if the window being switched to does exist.

To fulfill the playscript via your terminus, use the command below:

pytest -s

Below is the answer as expose on the terminal:

How to use BrowserStack to Execute Selenium Pytest Browser Automation Script

Using a platform like to action examination book is more commodious as you don ’ t have to manage dependencies yourself. With BrowserStack, you also get to admittance a vast to validate the functionality and consistent working of your app across 3500+ real device-OS-browser combination.

Here ’ s how you can use BrowserStack Automate to fulfil the Selenium Pytest Browser Automation Script

Prerequisites

Ensure you have Pytest v4+, Python3, and Pip3 instal on your local machine.

Talk to an Expert

Step to Execute the Selenium Pytest Browser Automation Script

Here BrowserStack Automate is used to execute the code snipping in the previous section with the undermentioned steps:

Step1:

Step 2:Install theBrowserStack SDKwithin your project ’ s root directory and execute the following command:

python3 -m pip install browserstack-sdk browserstack-sdk setup -- fabric `` pytest '' -- username `` YOUR_USERNAME '' -- key `` YOUR_ACCESS_KEY '' pip show browserstack-sdk

Step 3:Modify thebrowserstack.ymlfile within your project ’ s root directory as you see fit.

userName: & lt; YOUR_USERNAME & gt; accessKey: & lt; YOUR_ACCESSKEY & gt; framework: pytest platforms: - os: Windows osVersion: 10 browserName: Chrome browserVersion: 120.0 - os: OS X osVersion: Monterey browserName: Safari browserVersion: 15.6 - deviceName: iPhone 13 osVersion: 15 browserName: Chromium deviceOrientation: portrait parallelsPerPlatform: 1 browserstackLocal: true buildName: & lt; BUILD_NAME & gt; projectName: & lt; PROJECT_NAME & gt;

Step 4:Run the following command to execute your tryout:

browserstack-sdk pytest -s test_window_exception.py

Step 5:Go to your BrowserStack dashboard and click on “ Automate ” on the left sidebar.

You will see a result that looks as draw below:

Why is Testing on Real Devices and Browsers important?

The importance of testing applications on real device and browsers can never be overstated because it instills authority in the developers that a piece of software be ship is dependable after rigorous testing. It also indicates that end users of such applications would experience a very minimal incidence of bugs and crashes.

Testing on real device and browsers reveals first-hand issues that potential users of a piece of software would bump. Issues like disparity in UI across different device can be rectified by simulating human interaction with an application to determine how user-friendly it is.

One constraint about examine in this way is the unfitness to admission 100 of devices to conduct testing on. Conducting tests on a local gimmick is restrain, and this is why developers and many enterprises hug the use of online cloud testing platforms like BrowserStack.

A characteristic like solves some problems associate to testing in the following ways:

• Offers 3500+ desktop and mobile device, OS, and browser versions for cross-platform and.
• Simulation of across multiple platforms, devices, and browser.
• Identification of faults related to specific device.
• Provision of more reliable and exact results as you can configure tryout to accommodate variance in network, ironware, and operating scheme.
• Compatibility across respective versions of dependence and browser-specific method of rendering.

Conclusion

The NoSuchWindowException is elevate anytime the Selenium WebDriver try to access or interact with a quarry window because of an invalid name or previous closure.

This elision can be debar when certain conditional statements are added to a test book to verify that the targeted window exists and valid window names or hold are specified when a switch is being made.

Remember to constantly use Selenium waits (implicit, explicit) to wait for the complete cargo of the DOM tree and targeted elements. Most exceptions you ’ ll encounter can be resolved when elements, window tabs, and page content are allowed to fully load to completion.

For better restroom and entree to multiple real devices, you can execute your Selenium Pytest scripts with BrowserStack Automate.

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