Window handles in Selenium Python - Test Execution Trace

Test Overview

This test opens a new browser window, switches control to it, verifies the new window's title, then switches back to the original window and verifies its title.

Test Code - Selenium

Selenium Python

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
import unittest

class TestWindowHandles(unittest.TestCase):
    def setUp(self):
        self.driver = webdriver.Chrome()
        self.driver.get('https://example.com')

    def test_window_handles(self):
        driver = self.driver
        original_window = driver.current_window_handle

        # Click link that opens a new window
        link = WebDriverWait(driver, 10).until(
            EC.element_to_be_clickable((By.LINK_TEXT, 'More information...'))
        )
        link.click()

        # Wait for new window
        WebDriverWait(driver, 10).until(EC.new_window_is_opened([original_window]))

        # Switch to new window
        windows = driver.window_handles
        for window in windows:
            if window != original_window:
                driver.switch_to.window(window)
                break

        # Verify new window title
        self.assertIn('IANA', driver.title)

        # Switch back to original window
        driver.switch_to.window(original_window)

        # Verify original window title
        self.assertIn('Example Domain', driver.title)

    def tearDown(self):
        self.driver.quit()

if __name__ == '__main__':
    unittest.main()

Execution Trace - 9 Steps

Step	Action	System State	Assertion	Result
1	Test starts and opens browser to 'https://example.com'	Browser shows 'Example Domain' page	—	PASS
2	Stores current window handle as original_window	One browser window open with handle stored	—	PASS
3	Waits for and clicks link with text 'More information...' that opens new window	User clicks link, new window opening	—	PASS
4	Waits until new window is opened	Two browser windows open	—	PASS
5	Switches control to the new window	Driver controls new window	—	PASS
6	Checks that new window title contains 'IANA'	New window title visible	Assert 'IANA' in driver.title	PASS
7	Switches back to original window	Driver controls original window	—	PASS
8	Checks that original window title contains 'Example Domain'	Original window title visible	Assert 'Example Domain' in driver.title	PASS
9	Test ends and browser closes	No browser windows open	—	PASS

Failure Scenario

Failing Condition: The link with text 'More information...' is not found or clickable

Execution Trace Quiz - 3 Questions

What does the test do after clicking the link that opens a new window?

A Waits for the new window to open and switches to it

B Closes the original window immediately

C Refreshes the current page

D Clicks the link again

Key Result

Always store the original window handle before opening new windows, so you can switch back reliably after testing the new window.

Practice

1. What does driver.window_handles return in Selenium?

easy

A. The size of the browser window

B. The title of the current browser window

C. The URL of the current page

D. A list of all open browser window handles

Solution

1. Step 1: Understand the purpose of driver.window_handles

   This command returns all the unique IDs (handles) of open browser windows or tabs controlled by Selenium.

2. Step 2: Differentiate from other window properties

   It does not return titles, URLs, or sizes, only handles to switch between windows.

3. Final Answer:

   A list of all open browser window handles -> Option D

4. Quick Check:

   window_handles = list of handles [OK]

Hint: window_handles gives all open windows as a list [OK]

Common Mistakes:

• Confusing window_handles with current window title
• Expecting a single handle instead of a list
• Using window_handles to get URL or size

2. Which of the following is the correct syntax to switch to a new window using Selenium in Python?

easy

A. driver.switch.window(new_window_handle)

B. driver.switch_to.window(new_window_handle)

C. driver.switchTo().window(new_window_handle)

D. driver.switch_window(new_window_handle)

Solution

1. Step 1: Recall Selenium Python syntax for switching windows

   The correct method is driver.switch_to.window(handle) to switch context to the window with the given handle.

2. Step 2: Identify incorrect syntax options

   Options B, C, and D use incorrect method names or Java-like syntax not valid in Python Selenium.

3. Final Answer:

   driver.switch_to.window(new_window_handle) -> Option B

4. Quick Check:

   Use switch_to.window() in Python Selenium [OK]

Hint: Use driver.switch_to.window(handle) to switch windows [OK]

Common Mistakes:

• Using Java syntax like switchTo() in Python
• Missing '_to' in switch_to
• Using non-existent methods like switch_window

3. Given the following code snippet, what will be printed?

original_handle = driver.current_window_handle
all_handles = driver.window_handles
for handle in all_handles:
    if handle != original_handle:
        driver.switch_to.window(handle)
        print(driver.title)
        break

medium

A. The title of the original window

B. No output because loop never runs

C. The title of the new window (not original)

D. An error because of wrong handle usage

Solution

1. Step 1: Understand the code logic

   The code saves the original window handle, then loops through all handles. It switches to the first handle that is not the original.

2. Step 2: Determine what is printed

   After switching, it prints the title of the new window and breaks the loop, so it prints the new window's title.

3. Final Answer:

   The title of the new window (not original) -> Option C

4. Quick Check:

   Switch to non-original window, print title [OK]

Hint: Switch to non-original handle to get new window title [OK]

Common Mistakes:

• Expecting original window title to print
• Confusing current_window_handle with window_handles
• Thinking loop does not run

4. What is wrong with this code snippet for switching to a new window?

new_window = driver.window_handles[1]
driver.switch_to.window(new_window)
driver.close()

medium

A. Index 1 may not exist if only one window is open

B. switch_to.window() is not a valid method

C. It closes the new window instead of switching back

D. driver.close() closes all windows

Solution

1. Step 1: Analyze window_handles indexing

   Accessing index 1 assumes there are at least two windows open. If only one window exists, index 1 causes an IndexError.

2. Step 2: Check other statements

   switch_to.window() is valid, driver.close() closes only current window, so no issue there.

3. Final Answer:

   Index 1 may not exist if only one window is open -> Option A

4. Quick Check:

   Check window_handles length before indexing [OK]

Hint: Always check window_handles length before indexing [OK]

Common Mistakes:

• Assuming multiple windows always exist
• Thinking driver.close() closes all windows
• Confusing method names

5. You open a new tab in Selenium and want to switch to it, but you don't know its handle. Which code snippet correctly switches to the new tab?

hard

A. new_handle = [h for h in driver.window_handles if h != driver.current_window_handle][0]
driver.switch_to.window(new_handle)

B. driver.switch_to.window(driver.current_window_handle + 1)

C. driver.switch_to.window(driver.window_handles[-1])

D. driver.switch_to.window(driver.window_handles[0])

Solution

1. Step 1: Understand the problem

   You want to switch to the new tab but only know the current window handle, not the new one.

2. Step 2: Analyze each option

   new_handle = [h for h in driver.window_handles if h != driver.current_window_handle][0] driver.switch_to.window(new_handle) finds the handle that is not the current one and switches to it correctly.
   driver.switch_to.window(driver.current_window_handle + 1) tries to add 1 to a string handle, causing error.
   driver.switch_to.window(driver.window_handles[-1]) switches to the last handle, which may work but is unsafe if multiple windows exist.
   driver.switch_to.window(driver.window_handles[0]) switches back to the original window, not the new tab.

3. Final Answer:

   Use list comprehension to find new handle and switch -> Option A

4. Quick Check:

   Find new handle by exclusion, then switch [OK]

Hint: Find new handle by excluding current, then switch [OK]

Common Mistakes:

• Adding 1 to a string handle (invalid)
• Assuming last handle is always new
• Switching to original window by mistake