Selenium Tutorial to Speed Up Slow Test Cycles

Examples of Standard and Advanced Approaches to Decreasing Selenium Test Execution Time

Key Takeaways

  • Selenium is widely used for automated testing of web applications, but testers often face long test cycles.

  • Explore standard and advanced optimization Selenium tutorials to enhance test times including how to optimize your test cases, parallel testing, and dynamic page waits.

  • Even with these optimizations, due to their complexity and slower execution, Selenium tests are usually placed later in the pipeline. This leads to delayed feedback for developers, ranging from hours to days or even weeks.

  • Launchable cuts down Selenium execution time by intelligently generating dynamic test subsets. Select a subset of your Selenium tests to run on every pull request, for faster, timely feedback. 

Selenium is a widely-used open-source tool that enables developers and testers to automate browser actions and validate web applications. With its compatibility with multiple programming languages and browser platforms, it is no surprise that Selenium is the go-to choice for many software testing teams.

Selenium allows you to write automated test scripts in a variety of programming languages, including Java, Python, C#, Ruby, and more. It supports multiple browser platforms such as Chrome, Firefox, Safari, and IE. In this Selenium tutorial, we will focus on using Selenium with the Python language. 

One of the challenges with Selenium is the time it takes to execute test cases. In this hands-on Selenium tutorial, we cover standard and advanced tips and techniques to help you speed up test execution with Selenium, including how to apply Launchable’s Predictive Test Selection. 

Selenium Tutorial Basics: First Four Steps to Speed Up Selenium Test Execution

To get started, make sure you have Python and Selenium installed on your system. You can install Selenium with the following bash command: pip install selenium

To improve the speed of your Selenium test case execution, follow these four standard best practices, all aimed at significantly reducing your test execution time and increasing the efficiency of your automated testing process.

  1. Optimize Your Test Cases

    1. Prioritize test cases to focus on critical functionality first.

    2. Split large test suites into smaller, more manageable chunks.

    3. Remove redundant and outdated tests.

  2. Use Efficient Code

    1. Follow coding best practices, such as modularization, DRY (Don't Repeat Yourself) principle, and proper commenting.

    2. Optimize your code by using efficient algorithms and data structures.

    3. Regularly review and refactor your code to maintain efficiency.

  3. Reduce Page Load Time

    1. Minimize the use of heavy images, videos, and other media files.

    2. Use lazy loading for content that isn't immediately visible on the page.

    3. Optimize JavaScript and CSS files by minifying and compressing them.

  4. Implement Parallel Testing

    1. Run multiple test cases concurrently to reduce overall testing time.

    2. Use tools like Selenium Grid to distribute tests across multiple machines or browsers.

While all four of these best practices make your Selenium testing more efficient, they can only optimize them to a point. Many teams rely on parallel testing for faster test times, running tests concurrently. Although a common practice, it is finite; you can only parallelize your tests to your machine availability thresholds. The power of parallel testing is truly unleashed when combined with dynamic test subsets.

Advanced Selenium Tutorial Techniques for Faster Selenium Test Cycles (with Python Code Samples)

Selenium is widely used for automated testing of web applications, but testers often face slow test execution speed. Delays in Selenium test execution can be affected by a number of reasons including the size or complexity of the application, network latency, and bloated test suites.

To overcome these challenges, you can use advanced techniques to speed up Selenium testing – including the following practical code examples – to help you implement them in your own Selenium testing.

Use Headless Browsing

When using a headless browser, there is no need to open a physical browser window, which means that fewer system resources are used. This can speed up testing times and improve overall system performance.

  1. Run tests without opening the browser window, which saves resources and time.

  2. Use headless browser options like Headless Chrome, Microsoft Edge Puppeteer, or Firefox in headless mode.

Headless Browsing Python Example:

from selenium import webdriver 

options = webdriver.ChromeOptions() 
driver = webdriver.Chrome(options=options)

Browser Caching

We know that browser caching stores website data in the cache memory of the browser, allowing frequently visited websites to load faster. Enabling browser caching in Selenium tests can reduce the time it takes to load static content, making tests faster and more accurate, while also reducing the overall cost of testing.

  1. Enable browser caching to save time on loading static content during testing.

  2. Configure cache settings in your browser options

Configure Browser Cache Settings Python Example:

options = webdriver.ChromeOptions() 

Efficient Element Locating

By using these techniques with the page object model, Selenium tests can become more efficient and maintainable, resulting in faster test execution and greater confidence in the test results.

  1. Use unique and stable element identifiers (IDs, names, or CSS classes) when possible.

  2. Use XPath or CSS selectors when necessary but avoid using overly complex or long expressions.

  3. Use page object model (POM) to create a reusable and modular test structure that separates the logic and code of the test from the UI. 

  4. Avoid using sleep() statements as they add unnecessary delay to the test cycle and can cause unpredictable results. 

  5. Regularly review and update element locators to ensure they are still accurate and stable, especially if the application’s UI changes frequently. 

  6. Use browser developer tools to inspect the page’s HTML structure and identify unique element attributes that can be used as locators.

Dynamic Page Waits

Use Explicit Waits in Selenium to introduce dynamic page waits. Explicit waits require a specific condition to be met before proceeding with the next step of the test, helping to avoid timing issues and improve test reliability.

  1. Use explicit waits to pause the test execution until a specific condition is met, rather than using fixed sleep times.

  2. Utilize the WebDriverWait and ExpectedConditions classes in Selenium.

Dynamic Page Waits Python Example:

from import By 
from import WebDriverWait 
from import expected_conditions as EC 
element = WebDriverWait(driver, 10).until(     
      EC.presence_of_element_located((By.ID, "example_id")) 

While these advanced test optimization techniques can make your Selenium test runs more efficient, they do not solve bloated test suites. Testing earlier and often is the only solution to truly speed up Selenium test run time without sacrificing quality.

Trim Bloated Selenium Test Suites with Launchable for the Fastest Possible Test Runtimes

Selenium test suites are an essential part of ensuring product quality for several types of software. However, many teams face a common problem - long running tests that take up valuable time, resulting in reduced test frequency and delayed releases.

Due to their complexity and slower execution, Selenium tests usually run later in the software delivery lifecycle. This leads to delayed feedback for developers, ranging from hours to days or even weeks. By the time a test fails, developers may have forgotten the changes' context, causing additional time to fix the problem. Moreover, running such tests can deplete the team's testing budget.

Launchable cuts down Selenium execution time by intelligently generating dynamic test subsets. Select a subset of your Selenium tests to run on every pull request, for faster, timely feedback. 

Launchable's test intelligence platform uses a machine learning model to predict which tests in your test suite are likely to fail, depending on incoming changes. This pragmatic risk- based approach lowers testing time and thus expense while maintaining delivery speed and quality.

Teams can prioritize testing, ensuring the most critical tests are run more frequently, improving product quality and reducing risk. 

Launchable's main integration point is with your team's build tool or test runner, rather than the test framework itself. So, if you're using the Selenium framework, it's important to determine which tool you use to start your tests, including:

There’s nothing extra you need to do with Selenium to take advantage of Launchable’s Predictive Test Selection. All you need to do is set up Launchable for your test runner - no test changes needed. Launchable setup is simple:

  1. Sign up for a Launchable account at

  2. After creating your user account and verifying your email address (if necessary), you'll be prompted to create an Organization for your company and a Workspace for your test suite.

  3. Then start sending your test data to Launchable.

Enjoy the benefits of early feedback and faster releases, without sacrificing quality with Launchable. Connect with a Launchable Astronaut today!

Selenium Tutorial Takeaways

Selenium is a powerful tool, but your Selenium tests often are pushed to later in your testing pipeline because of their length and complexity. Optimizing your Selenium tests with the shared tutorials and running the right Selenium tests earlier in your testing cycles will speed up your test times. Launchable integrates seamlessly with your Selenium tests, no matter which test orchestrator you are using, so you can start selecting the most critical and relevant tests, optimizing your testing workflow, and get quicker feedback as soon as today.

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