Selenium: Implicit vs Explicit Waits
In today's web development landscape, AJAX techniques dominate, leading to the asynchronous loading of web elements at different intervals. This asynchronous behavior often poses a challenge when it comes to locating and interacting with elements. Failure to locate a dynamic element in the Document Object Model (DOM) can result in the dreaded "ElementNotVisibleException" exception. Selenium WebDriver comes to the rescue with its built-in wait mechanisms, providing a solution to this issue. In this comprehensive guide, we will delve into the two types of waits offered by Selenium
Understanding Implicit Waits: Patience in Element Discovery
Implicit waits in Selenium WebDriver are borrowed from the Watir framework and serve as a mechanism to instruct the WebDriver to wait for a specified duration while attempting to locate an element. Implicit waits are primarily used when elements are not immediately available in the DOM. Once set, the implicit wait duration persists for the entire lifespan of the WebDriver object, unless altered again. This valuable feature allows Selenium to patiently wait for an element to appear on the page before throwing an exception.
Implicit Waits Behavior: A Closer Look
Let's explore various scenarios to understand how implicit waits behave:
1. When No Default Implicit Wait is Defined for a Non-Existing Element: In this scenario, where no default implicit wait is defined for finding a non-existing element, the WebDriver immediately reports the absence of the element.
2. When a Default Implicit Wait is Defined for a Non-Existing Element: If a default implicit wait is set, the WebDriver patiently waits for the specified duration before raising an exception if the element is not found.
3. Altering Implicit Wait for a Non-Existing Element: The implicit wait duration can be modified at any time during the WebDriver's execution. It waits according to the new duration when searching for non-existing elements.
4. Altering Implicit Wait for an Existing Element: Interestingly, even if the implicit wait duration is altered, the WebDriver swiftly locates an existing element, resulting in no wait time.
Understanding Explicit Waits Precision Timing for Element Interaction:
Explicit waits are a powerful feature that allows developers to specify conditions that must be met before proceeding with code execution. Unlike implicit waits, explicit waits are defined for specific elements or actions, providing fine-grained control over element interactions. WebDriverWait, in combination with ExpectedConditions, is the core of explicit waits in Selenium WebDriver.
Common Explicit Wait Conditions
Selenium WebDriver offers various built-in explicit wait conditions, making it easier to handle different scenarios, such as waiting for elements to become clickable, visible, or to meet specific test conditions.
Avoiding the Mixing of Implicit and Explicit Waits
One critical aspect of working with waits in Selenium is avoiding the simultaneous use of both implicit and explicit waits on the same WebDriver instance. Mixing these two types of waits can lead to undefined behavior, making predicting the exact waiting times challenging. In scenarios where explicit waits are required, it's recommended to refrain from using implicit waits to ensure predictable behavior.
Conclusion
Selenium WebDriver provides two essential tools for handling asynchronous web elements: Implicit Waits and Explicit Waits. Understanding when and how to use each type of wait is crucial for efficient element handling in your automated tests. By mastering these wait mechanisms, you can ensure your WebDriver scripts smoothly interact with dynamic web pages, enhancing the reliability and robustness of your automated tests.
