Future trend of automated testing ----- self healing technology

  Automated testing future trend series ： self-healing （Self-Healing） technology

1. Self healing technology

self-healing （Self-Healing） Technology in computer terminology means ： A self-healing management mechanism .

Analogy to life , When a living body suffers some small damage , Their bodies can often achieve self-healing through their own repair mechanism , Without outside intervention . Such as gecko's broken tail regeneration , Or the body regeneration ability of crabs .

Back to the computer world , Self healing technology is also widely used , For example, the information channel of the chip is self-healing , Software system fault self-healing, etc . So what we want to introduce here is a self-healing technology in the direction of automated testing ：

You can find unexpected errors in the execution of its test script and change them without human intervention , So as to restore itself to a better running state .

2. Technical principle

Problem domain ： Using self-healing technology in automated testing mainly solves Object recognition problem .

Traditional automated testing frameworks and tools use application models to define application components and objects and their attributes . These definitions are then used to identify and manipulate application components . But applications change frequently when they are updated . May be intentional developer changes or immediate （ By the application system or build process ） the . These changes undermine our traditional automation approach based on static definitions .

natural language processing （NLP） And machine learning (ML) And other intelligent technologies have been developed to test scripts “ Study ” and “ To adapt to ” The point of . Use of self-healing test automation tools AI And machine learning technology , According to the user interface (UI) Or changes in the application environment can automatically update and adjust the test process .

When running tests , They scan the user interface of the application to see if there are any objects . Then they compare them with the application model previously generated for automated testing . If there are any changes to the application , There is a technology that allows tests to adapt and update automatically . This ability is called “ Self repair ”. Property changes are automatically sensed , Internal scripts repair themselves at run time by repairing themselves .

The self-healing function has the following characteristics ：

• In the process of execution , If a test step locator cannot be detected by its default locator value , Other locator policies in the list will be automatically applied , No manual intervention by the tester is required . Execution will continue , It's like there's no fault .
• In the process of execution , If the test step locator fails and cannot be automatically detected using any other locator strategy , test Will be suspended , Allows the user to select the relevant element and continue . The new locator policy will be automatically updated the next time it is executed .

The following figure describes the main steps of self-healing technology ：

The advantages of automatic test self-healing technology mainly include ：

• Reduce test failure rate

  It is normal that the test execution fails , But sometimes the root cause of failure is simply because the user interface has changed and the test script has not changed synchronously . After using self-healing technology , It is unlikely that script execution failure will be affected by the object location that cannot be correctly recognized . The traditional automation framework cannot recognize these changes and update them automatically .

• Prevent test instability

  If we have flaky tests exist , It is difficult for us to determine whether our test is stable .”Nosuchelementexception“ Errors are one of the several errors that make test design unstable , It is very difficult for the test team to completely control such phenomena . When our test design is consistent with the application , The test is less likely to fail during execution , And the execution process is more smooth .

• Improve script maintainability

  The changes in the test code are proportional to the changes made by the developer in the application . Because the root cause may change and cannot reflect AUT True state and performance , Therefore, failed test results will limit testers' access to meaningful insights about their tests . By identifying and updating any changed test cases in the user interface , Self healing technology saves the time and energy of agile test and development teams . In addition to time and energy , Self repair in test automation also significantly reduces test maintenance costs .

3. Industry practice

We can see , There are already some good practices in the industry , such as Healenium project .

With Healenium Project as an example , See how automated test self-healing technology works ：

Suppose we go through id To locate a button on our application interface , The positioner should be ：#button

  You can see from the above picture that , Elements can be correctly positioned to .Healnium Will save the correct positioner , As the benchmark value for the next test execution .

Now? , Let's assume that the developer changes the... Of the application UI Interface , Changed the of this button id attribute , from #button Changed to: #green_button. But for some reason , The test team was not notified of this change , So the test script has not been updated . So when we execute the script again , Trying to use #button When the old positioner goes to position the button , The script will report an error , Tips “NoSuchElement” The error exception of .

under these circumstances , standards-of-use Selenium The implementation test will fail , But use Healenium Will not be . Healenium Capture NoSuchElement abnormal , Trigger machine learning algorithm , Pass the current page status , Get the previously successful locator path , Compare them , And generate a list of fixed locators . It takes the locator with the highest score and uses it to perform operations . As we can see, the element was successfully found and passed the test .

After the test runs ,Healenium Generate a report , It contains information about repairing locators 、 Screenshot and all details of the repair success feedback button .

If the repair is successful , We can use Healenium Idea Plug in updates our automated test code ： The plug-in uses the repair locator to find, repair, and update test code .

 Healenium Use a machine learning algorithm to analyze the changes of the current web page ： The longest common subsequence algorithm based on weight

More details about this project , You can visit the official website of this project ：https://healenium.io/

The longest common subsequence algorithm based on weight

Through this case , Let's compare the differences in object maintenance between traditional automated testing methods and automated testing methods based on self-healing technology （ As shown in the figure below ）：

  Traditional automated testing methods and automated testing methods based on self-healing technology

4. Summary

The above briefly introduces the background and practice of automatic test self-healing technology . The future development trend of automated testing is bound to be more and more intelligent , Therefore, more intelligent technologies will be applied to the field of automated testing , So as to improve the efficiency of automated testing .

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