One essential aspect of Selenium is handling synchronization issues (for example, AJAX loading screen), where the automation script needs to wait for specific conditions to be met before proceeding. This is where “Expected Conditions” come into play, providing a flexible and efficient way to wait for elements or certain states to appear or change on a web page.

What are Expected Conditions?

Expected Conditions are predefined conditions that Selenium can wait for, ensuring that the desired state or element is available before performing an action or assertion. These conditions are part of the selenium.webdriver.support.expected_conditions module and can be used in conjunction with the WebDriverWait class to implement effective synchronization in your automation scripts.

Key Expected Conditions and Examples:

  1. element_to_be_clickable This condition waits for an element to be clickable, i.e., both visible and enabled, before proceeding. It is commonly used before clicking on buttons, links, or input fields.
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from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.ui import WebDriverWait

btn = WebDriverWait(driver, 10).until(EC.element_to_be_clickable((By.ID, 'submit-btn')))
btn.click()
  1. visibility_of_element_located This condition waits for an element to be visible on the page before proceeding. It is useful when waiting for elements to load or become visible before interacting with them.
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element = WebDriverWait(driver, 10).until(EC.visibility_of_element_located((By.XPATH, '//div[@class="element_class"]')))
# Perform actions on the element
  1. text_to_be_present_in_element This condition waits for a specific text to be present within an element before proceeding. It can be helpful when verifying that certain text content has loaded or changed on a page.
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element = WebDriverWait(driver, 10).until(EC.text_to_be_present_in_element((By.ID, 'element_id'), 'expected_text'))
# Continue with further assertions or actions
  1. title_contains: This condition waits for the page title to contain a specific text before proceeding. It is useful for verifying that the correct page has loaded.
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WebDriverWait(driver, 10).until(EC.title_contains('expected_title'))
# Perform actions on the loaded page

There are a lot more possible conditions. Full list can be found on official Selenium documentation.

By utilizing Expected Conditions in Selenium with Python, you can effectively handle synchronization issues and ensure that your automation scripts interact with web elements only when they are in the expected state.