Custom wait conditions in Selenium Python - Framework Patterns

Framework Mode - Custom wait conditions

Folder Structure

my_selenium_project/
├── tests/
│   ├── test_login.py
│   └── test_checkout.py
├── pages/
│   ├── base_page.py
│   ├── login_page.py
│   └── checkout_page.py
├── waits/
│   └── custom_waits.py
├── utils/
│   ├── logger.py
│   └── config_reader.py
├── config/
│   ├── dev_config.yaml
│   ├── prod_config.yaml
│   └── test_config.yaml
├── conftest.py
└── requirements.txt

Test Framework Layers

• Driver Layer: Manages browser setup and teardown, usually in conftest.py using pytest fixtures.
• Page Objects: Classes in pages/ folder representing web pages with element locators and actions.
• Custom Waits: Functions or classes in waits/custom_waits.py defining special wait conditions beyond built-in Selenium waits.
• Tests: Test scripts in tests/ folder that use page objects and custom waits to perform validations.
• Utilities: Helper modules like logging and configuration readers in utils/.
• Configuration: Environment-specific settings stored in config/ folder.

Configuration Patterns

• Environment Files: Use YAML files in config/ to store URLs, credentials, and browser preferences for dev, test, and prod.
• Config Reader Utility: A Python module in utils/config_reader.py to load and parse config files based on environment variable.
• Browser Setup: In conftest.py, read config to launch desired browser with options.
• Credentials Handling: Store sensitive data in config files excluded from version control or use environment variables.

Test Reporting and CI/CD Integration

• Test Reports: Use pytest with plugins like pytest-html or pytest-allure to generate readable HTML or Allure reports.
• Logging: Centralized logging in utils/logger.py to capture test steps and errors.
• CI/CD: Integrate tests in pipelines (GitHub Actions, Jenkins) to run on code push, with reports archived and notifications sent.
• Custom Waits Impact: Custom wait conditions improve test stability by waiting for specific page states before actions.

Best Practices for Custom Wait Conditions Framework

1. Use Explicit Waits: Prefer explicit waits with custom conditions over implicit waits for better control and reliability.
2. Keep Waits Reusable: Write custom wait functions or classes that can be reused across multiple tests and pages.
3. Timeouts and Polling: Set sensible timeout and polling intervals to balance test speed and stability.
4. Fail Fast: Custom waits should raise clear exceptions when conditions are not met to help debugging.
5. Separate Wait Logic: Keep custom wait conditions in their own module/folder to keep code organized and maintainable.

Self Check Question

Where in this folder structure would you add a new custom wait condition that waits for a specific animation to finish on a page?

Key Result

Organize custom wait conditions in a dedicated module to improve test reliability and maintainability.

Practice

1. What is the main purpose of creating a custom wait condition in Selenium with Python?

easy

A. To automatically retry failed tests

B. To speed up the test execution by skipping waits

C. To replace the WebDriverWait class completely

D. To wait for a specific condition that is not covered by built-in waits

Solution

1. Step 1: Understand built-in waits limitations

   Built-in waits cover common cases but sometimes you need to wait for a unique condition.

2. Step 2: Purpose of custom wait

   Custom waits let you define exactly what to wait for, improving test reliability.

3. Final Answer:

   To wait for a specific condition that is not covered by built-in waits -> Option D

4. Quick Check:

   Custom wait = wait for unique condition [OK]

Hint: Custom waits handle unique conditions not in built-in waits [OK]

Common Mistakes:

• Thinking custom waits speed up tests
• Believing custom waits replace WebDriverWait
• Assuming custom waits retry tests automatically

2. Which of the following is the correct way to define a custom wait condition class in Selenium Python?

easy

A. class MyWait:
def __call__(self, driver):
return driver.find_element_by_id('myid')

B. class MyWait:
def wait(self):
return True

C. def MyWait(driver):
return driver.find_element('id', 'myid')

D. class MyWait:
def wait_for(self, driver):
return False

Solution

1. Step 1: Identify the special method for custom waits

   Custom wait classes must implement the __call__ method to be callable by WebDriverWait.

2. Step 2: Check method signature and return

   Method __call__ takes driver and returns element or True when condition met.

3. Final Answer:

   class MyWait:\n def __call__(self, driver):\n return driver.find_element_by_id('myid') -> Option A

4. Quick Check:

   Custom wait uses __call__ method [OK]

Hint: Custom wait class must have __call__(self, driver) method [OK]

Common Mistakes:

• Using method named wait instead of __call__
• Defining function instead of class
• Using wrong method signature

3. Given the code below, what will be the output if the element with id 'submit' appears after 3 seconds?

from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.common.by import By

class WaitForSubmit:
    def __call__(self, driver):
        try:
            elem = driver.find_element(By.ID, 'submit')
            return elem
        except:
            return False

wait = WebDriverWait(driver, 5)
submit_button = wait.until(WaitForSubmit())
print(submit_button.tag_name)

medium

A. Prints False

B. Raises TimeoutException immediately

C. Prints the tag name of the 'submit' element after waiting

D. Raises NoSuchElementException

Solution

1. Step 1: Understand the custom wait behavior

   The custom wait tries to find element with id 'submit'. If not found, returns False to keep waiting.

2. Step 2: Analyze wait.until with timeout 5 seconds

   The element appears after 3 seconds, so wait.until returns the element before timeout.

3. Final Answer:

   Prints the tag name of the 'submit' element after waiting -> Option C

4. Quick Check:

   Element appears before timeout, so tag_name prints [OK]

Hint: Custom wait returns element or False; wait.until waits until element found [OK]

Common Mistakes:

• Assuming immediate TimeoutException
• Expecting print of False instead of element
• Confusing exceptions raised

4. Identify the error in the following custom wait condition code:

class WaitForText:
    def __call__(self, driver):
        element = driver.find_element(By.ID, 'message')
        if element.text == 'Done':
            return True
        else:
            return None

wait = WebDriverWait(driver, 10)
wait.until(WaitForText())

medium

A. Returning None instead of False causes wait.until to stop waiting

B. Missing import for By causes NameError

C. Returning True instead of element causes error

D. Using find_element instead of find_elements causes exception

Solution

1. Step 1: Check imports

   The code uses By.ID but does not import By, causing NameError at runtime.

2. Step 2: Analyze return values

   Returning True or None is allowed; wait.until treats True as success and None as failure to continue waiting.

3. Final Answer:

   Missing import for By causes NameError -> Option B

4. Quick Check:

   By must be imported to avoid NameError [OK]

Hint: Always import By before using it in locators [OK]

Common Mistakes:

• Thinking None stops waiting (it continues)
• Assuming returning True causes error
• Confusing find_element with find_elements

5. You want to wait until a button with id 'start' is both visible and enabled before clicking it. Which custom wait condition class correctly implements this?

hard

A. class WaitForStart:
def __call__(self, driver):
btn = driver.find_element(By.ID, 'start')
if btn.is_displayed() and btn.is_enabled():
return btn
return False

B. class WaitForStart:
def __call__(self, driver):
btn = driver.find_element(By.ID, 'start')
if btn.is_displayed() or btn.is_enabled():
return True
return False

C. class WaitForStart:
def __call__(self, driver):
btn = driver.find_element(By.ID, 'start')
if btn.is_displayed() and btn.is_enabled():
return True
return False

D. class WaitForStart:
def __call__(self, driver):
btn = driver.find_element(By.ID, 'start')
if btn.is_enabled():
return btn
return None

Solution

1. Step 1: Check condition logic

   We need both visible and enabled, so use 'and' operator to check both.

2. Step 2: Return element when condition met

   Return the button element so wait.until returns it for further actions.

3. Final Answer:

   class WaitForStart:\n def __call__(self, driver):\n btn = driver.find_element(By.ID, 'start')\n if btn.is_displayed() and btn.is_enabled():\n return btn\n return False -> Option A

4. Quick Check:

   Return element when visible and enabled [OK]

Hint: Return element only if visible AND enabled, else False [OK]

Common Mistakes:

• Using 'or' instead of 'and' for conditions
• Returning True instead of element
• Returning None instead of False