Selenium
March 17, 2021

How to Make Selenium More Stable with Self-Healing Tests

Scriptless Testing

Testers are increasingly turning to self-healing tests in order to combat one of the biggest challenges of test automation: test flakiness. 

To better understand why self-healing tests are so important, let’s first discuss what contributes to flaky and unreliable test scripts in the first place. 

Why Test Flakiness Still Exists 

Most software testing teams have had to encounter flaky automated tests at one point or another. It’s unfortunately come to be an expected part of the test automation package.  

Here are some of the top reasons for test flakiness

5 Common Reasons for Test Flakiness

1. Having tests that are dependent on one another 

2. Not having the right testing framework 

3. Lack of ongoing maintenance (consistent failures without action by testers) 

4. No proper synchronization 

5. Badly written tests 

Another main reason why test flakiness is a persistent problem, especially with Selenium, is because these tests often use incorrect object identifiers. Whether by solely using XY coordinates or a flaky XPath, tests that do not identify test elements properly break often and require a lot of maintenance.  

Selenium testers have a particular issue with test flakiness since Selenium does not have any self-healing capabilities as a standalone solution. Therefore, a company that automates their tests with Selenium scripts will need to scour the code to and resolve issues manually every time a test fails. For every new functionality that the developers add to their application, these test scripts will continue to become more and more unreliable. Quality debt will continue to increase to the point where test automation will not be able to keep up with new releases.  

Benefits of Self-Healing Selenium Scripts 

An increasing number of Selenium testers have turned to design self-healing Selenium scripts to combat this issue of unreliability. By creating self-healing tests, testers build scenarios that can locate web elements more accurately. This happens even when the application’s UI changes frequently (as is the case with most companies).  

Not only do self-healing Selenium scripts reduce the time spent on maintaining tests, but these scripts also come with many other benefits. With self-healing tests doing a lot of the busy work, testers finally have the time they need to build tests that validate a wider range of application functionalities on a more in-depth level. Furthermore, high-quality tests allow for expedited feedback and a faster resolution of issues that do come up. These additional benefits contribute to faster releases over time, creating a ripple effect of testing productivity and effectiveness.  

Additionally, certain self-healing technologies can also take advantage of increasing test data by adapting to tests and learning about which element attributes will most likely change over time. This can help testing teams achieve greater agility, as well as a “shift-left” mindset that allows them to test earlier in the software development process.  

Lastly, with highly reliable test cases that can heal themselves, the testers increase their level of trust within the organization and receive better support from developers. 

How Self-Healing Tests Work 

There are various test automation tools on the market that use self-healing technology. Let us look at two prime examples: 

Perfecto Scriptless’s AI-Based, Self-Healing Algorithm 

Perfecto Scriptless’s self-healing capability comes from its AI-based algorithm, which combines codeless test automation with machine learning. It incorporates two different algorithms to identify a test object properly: technical HTML attributes and weight distribution algorithms. 

By attributing more weight to a test object’s less fragile attributes, Perfecto Scriptless’s self-healing tests allow for automatic updates in the test flow. This makes the test more resilient, reducing the time and resources needed for proper test maintenance. 

Consider an example of a company changing the size or position of its login button on their homepage. While developers may do this to improve the end-user experience, testers need to account for this change not only for a login test flow, but for all other test flows that require the user to log in to their account.  

Perfecto Scriptless’s self-healing algorithm uses machine learning to accomplish two goals when building automated tests. First, these self-healing tests can overcome changes like the login button automatically, preventing the test that includes that element from breaking without human involvement. Second, this change applies to every other test that uses this updated element, reducing test maintenance overhead dramatically. 

Healenium Self-Healing with Perfecto 

Another option for building self-healing tests is through Perfecto’s integration with Healenium, an open-source solution that provides self-healing changes to updated Selenium web elements during run-time.  

Also using machine learning, Healenium handles NoSuchElement test failures by replacing failed controls with new values that best match these previous elements. Then, it re-runs the test with the replaced control successfully.  

Healenium Smart Reporting with Perfecto

For Perfecto users, it is very simple to get started with Healenium. All it takes is wrapping the Selenium driver with the SelfHealingDriver, and Perfecto tests can begin the self-healing process. Testers need to execute at least one test case successfully before Healenium can begin healing failed test elements. Once this happens, object properties are stored in a localized Docker container and Postgres database for the Healenium backend. 

Do Self-Healing Tests Actually Work? 

One frequent question that comes up in discussions surrounding self-healing tests is whether they actually work.  

There are two important points to consider when answering this question: the self-healing tests’ accuracy rates and misclassification rates. While accuracy rates refer to the amount of true positive and true negative results you get when testing, misclassification rates measure these test scripts’ false positives and false negatives.  

According to data from Perfecto Scriptless customers, their self-healing tests are over 97% accurate in accounting for changes in web applications. In other words, in over 97% of cases, Perfecto Scriptless either identifies the element accurately to overcome UI changes, or identifies a bug correctly and causes the test to fail accordingly.  

If you are looking to make this kind of impact on your testing environment, try self-healing tests with Perfecto Scriptless today.  

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