Fluent waits in Selenium Python - Build an Automation Script

Verify dynamic loading of element using Fluent Wait

Preconditions (2)

Step 1: Open the test page URL in a browser

Step 2: Click the button that triggers loading of the hidden element

Step 3: Use Fluent Wait to wait for the hidden element to be visible

Step 4: Verify that the hidden element is displayed on the page

✅ Expected Result: The hidden element becomes visible after clicking the button and the test verifies its visibility successfully using Fluent Wait

Automation Requirements - Selenium with Python

Assertions Needed:

Assert the hidden element is displayed after waiting

Assert no timeout exception occurs during wait

Best Practices:

Use Fluent Wait with polling interval and timeout

Handle exceptions like NoSuchElementException during wait

Use By locators for element identification

Avoid hardcoded sleeps; rely on waits

Automated Solution

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
from selenium.common.exceptions import NoSuchElementException
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support.wait import FluentWait
import time

# Setup WebDriver (Chrome example)
driver = webdriver.Chrome()
try:
    driver.get('https://example.com/dynamic_loading')  # Replace with actual test URL

    # Click the button to start loading hidden element
    start_button = driver.find_element(By.ID, 'startButton')
    start_button.click()

    # Setup Fluent Wait: timeout 15 seconds, polling every 1 second
    wait = WebDriverWait(driver, 15, poll_frequency=1, ignored_exceptions=[NoSuchElementException])

    # Wait until the hidden element is visible
    hidden_element = wait.until(EC.visibility_of_element_located((By.ID, 'hiddenElement')))

    # Assert the element is displayed
    assert hidden_element.is_displayed(), 'Hidden element should be visible after wait'

finally:
    driver.quit()

This script opens the test page and clicks the button that triggers loading of a hidden element.

It uses Selenium's WebDriverWait with a polling interval of 1 second and a timeout of 15 seconds to implement a Fluent Wait.

The wait ignores NoSuchElementException during polling to avoid failing early.

Once the hidden element is visible, the script asserts it is displayed.

Finally, the browser is closed to clean up.

Common Mistakes - 4 Pitfalls

Using time.sleep() instead of Fluent Wait

Not ignoring exceptions during wait

Using hardcoded XPath locators

Not quitting the driver after test

Bonus Challenge

Now add data-driven testing with 3 different buttons that load different hidden elements using Fluent Wait

Show Hint

Practice

1. What is the main purpose of using a FluentWait in Selenium Python?

easy

A. To pause the test execution for a fixed time

B. To repeatedly check for a condition until it is met or a timeout occurs

C. To immediately find an element without waiting

D. To run tests in parallel threads

Solution

1. Step 1: Understand FluentWait behavior

   FluentWait repeatedly checks for a condition, like element presence, until timeout or success.

2. Step 2: Compare options

   Only To repeatedly check for a condition until it is met or a timeout occurs describes this repeated checking with timeout. Others describe different concepts.

3. Final Answer:

   To repeatedly check for a condition until it is met or a timeout occurs -> Option B

4. Quick Check:

   FluentWait = repeated checks with timeout [OK]

Hint: FluentWait keeps trying until success or timeout [OK]

Common Mistakes:

• Confusing FluentWait with fixed sleep
• Thinking FluentWait runs tests in parallel
• Assuming FluentWait finds elements instantly

2. Which of the following is the correct way to create a FluentWait object in Selenium Python?

easy

A. wait = FluentWait(driver).with_timeout(10).polling_every(1).ignoring(NoSuchElementException)

B. wait = FluentWait(driver, timeout=10, poll_interval=1, ignored_exceptions=[NoSuchElementException])

C. wait = WebDriverWait(driver, 10).pollingEvery(1).ignoring(NoSuchElementException)

D. wait = FluentWait(driver).timeout(10).poll(1).ignore(NoSuchElementException)

Solution

1. Step 1: Recall FluentWait syntax in Selenium Python

   The correct syntax chains methods: with_timeout(), polling_every(), ignoring() on FluentWait instance.

2. Step 2: Analyze options

   wait = FluentWait(driver).with_timeout(10).polling_every(1).ignoring(NoSuchElementException) matches correct chaining syntax. wait = FluentWait(driver, timeout=10, poll_interval=1, ignored_exceptions=[NoSuchElementException]) uses wrong constructor parameters. wait = WebDriverWait(driver, 10).pollingEvery(1).ignoring(NoSuchElementException) uses WebDriverWait, not FluentWait. wait = FluentWait(driver).timeout(10).poll(1).ignore(NoSuchElementException) uses incorrect method names.

3. Final Answer:

   wait = FluentWait(driver).with_timeout(10).polling_every(1).ignoring(NoSuchElementException) -> Option A

4. Quick Check:

   FluentWait chaining methods = wait = FluentWait(driver).with_timeout(10).polling_every(1).ignoring(NoSuchElementException) [OK]

Hint: FluentWait uses chained methods like with_timeout() [OK]

Common Mistakes:

• Using WebDriverWait instead of FluentWait
• Passing parameters directly to constructor
• Using wrong method names like timeout()

3. What will be the output of the following code snippet if the element with id 'submit' appears after 3 seconds?

from selenium.webdriver.support.ui import FluentWait
from selenium.common.exceptions import NoSuchElementException

wait = FluentWait(driver).with_timeout(5).polling_every(1).ignoring(NoSuchElementException)
element = wait.until(lambda d: d.find_element('id', 'submit'))
print(element.tag_name)

medium

A. Raises NoSuchElementException after 5 seconds

B. Raises TimeoutException immediately

C. Prints the tag name of the 'submit' element after about 3 seconds

D. Prints None immediately

Solution

1. Step 1: Understand FluentWait timing

   FluentWait waits up to 5 seconds, checking every 1 second, ignoring NoSuchElementException.

2. Step 2: Analyze element appearance

   The element appears after 3 seconds, which is within the 5-second timeout, so wait.until returns the element.

3. Step 3: Print element tag name

   After wait.until returns, print outputs the tag name of the found element.

4. Final Answer:

   Prints the tag name of the 'submit' element after about 3 seconds -> Option C

5. Quick Check:

   Element found within timeout = prints tag name [OK]

Hint: FluentWait waits until element appears or timeout [OK]

Common Mistakes:

• Expecting immediate TimeoutException
• Thinking NoSuchElementException is raised
• Assuming print outputs None

4. Identify the error in this FluentWait usage:

wait = FluentWait(driver).with_timeout(10).polling_every(2)
element = wait.until(lambda d: d.find_element_by_id('login'))

medium

A. Using deprecated method find_element_by_id instead of find_element

B. Missing ignoring() to handle exceptions

C. Polling interval is too long

D. Timeout value should be in milliseconds

Solution

1. Step 1: Check method usage for element finding

   In Selenium Python 3.12+, find_element_by_id is deprecated; use find_element('id', 'login').

2. Step 2: Review other options

   Ignoring exceptions is optional but recommended; polling_every uses seconds; timeout is in seconds, so no error there.

3. Final Answer:

   Using deprecated method find_element_by_id instead of find_element -> Option A

4. Quick Check:

   Deprecated method usage = Using deprecated method find_element_by_id instead of find_element [OK]

Hint: Use find_element with locator tuple, not deprecated methods [OK]

Common Mistakes:

• Ignoring deprecation warnings
• Confusing polling interval units
• Assuming timeout needs milliseconds

5. You want to wait for a button with CSS selector '.submit-btn' to be clickable, checking every 500 milliseconds, with a timeout of 8 seconds, ignoring ElementNotInteractableException. Which FluentWait code snippet correctly implements this?

hard

A. wait = FluentWait(driver).with_timeout(8).polling_every(0.5).ignoring(ElementNotInteractableException)
element = wait.until(lambda d: d.find_element('css selector', '.submit-btn').is_enabled())

B. wait = FluentWait(driver).with_timeout(8).polling_every(0.5).ignoring(ElementNotInteractableException)
element = wait.until(lambda d: d.find_element_by_css_selector('.submit-btn').is_enabled())

C. wait = FluentWait(driver).with_timeout(8).polling_every(0.5).ignoring(ElementNotInteractableException)
element = wait.until(lambda d: d.find_element('css selector', '.submit-btn').clickable())

D. wait = FluentWait(driver).with_timeout(8).polling_every(0.5).ignoring(ElementNotInteractableException)
element = wait.until(lambda d: d.find_element('css selector', '.submit-btn') if d.find_element('css selector', '.submit-btn').is_enabled() else False)

Solution

1. Step 1: Set FluentWait with correct timeout, polling, and ignoring

   All options set timeout 8s, polling 0.5s, ignoring ElementNotInteractableException correctly.

2. Step 2: Check lambda condition for clickable

   wait = FluentWait(driver).with_timeout(8).polling_every(0.5).ignoring(ElementNotInteractableException) element = wait.until(lambda d: d.find_element('css selector', '.submit-btn') if d.find_element('css selector', '.submit-btn').is_enabled() else False) returns the element only if is_enabled() is True; else returns False to keep waiting. This is correct usage.

3. Step 3: Identify errors in other options

   wait = FluentWait(driver).with_timeout(8).polling_every(0.5).ignoring(ElementNotInteractableException) element = wait.until(lambda d: d.find_element('css selector', '.submit-btn').is_enabled()) returns boolean from is_enabled(), not element; wait = FluentWait(driver).with_timeout(8).polling_every(0.5).ignoring(ElementNotInteractableException) element = wait.until(lambda d: d.find_element('css selector', '.submit-btn').clickable()) uses non-existent clickable() method; wait = FluentWait(driver).with_timeout(8).polling_every(0.5).ignoring(ElementNotInteractableException) element = wait.until(lambda d: d.find_element_by_css_selector('.submit-btn').is_enabled()) uses deprecated find_element_by_css_selector.

4. Final Answer:

   wait = FluentWait(driver).with_timeout(8).polling_every(0.5).ignoring(ElementNotInteractableException)\nelement = wait.until(lambda d: d.find_element('css selector', '.submit-btn') if d.find_element('css selector', '.submit-btn').is_enabled() else False) -> Option D

5. Quick Check:

   Return element only when clickable = wait = FluentWait(driver).with_timeout(8).polling_every(0.5).ignoring(ElementNotInteractableException)\nelement = wait.until(lambda d: d.find_element('css selector', '.submit-btn') if d.find_element('css selector', '.submit-btn').is_enabled() else False) [OK]

Hint: Return element only when condition true inside wait.until lambda [OK]

Common Mistakes:

• Returning boolean instead of element in wait.until
• Using deprecated find_element_by_css_selector
• Calling non-existent clickable() method