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Automated Regression Testing: A Detailed Guide

By Kitakabee, Community Contributor -

Table of Contents

Regression Testing is defined as a type of software testing that is carried out in order to ensure that a recent code change has not impacted the existing functionalities adversely. In other words, you can also say regression testing is basically re-running our existing test suites to ensure existing functionalities work fine. 

Now, you can imagine if this regression testing has to be done manually, it defies the entire purpose of regression testing as manual testing is prone to errors and ends up consuming much more time; plus a person doing the same set of tests, again and again, can be very mundane and hence, Automated Regression Testing can be a boon. 

It is faster, quicker, efficient and ensures that the existing product works properly with new features as well before releasing them.

What is Automation Regression Testing?

Now, before getting into how to carry out Regression Testing and what are the benefits of it, let’s make sure you have a clear idea of what “Regression Testing” means. 

Regression testing is conducted once some code changes have gone in; the changes can be due to some new feature or could be due to some bug fixes as well.

Unfortunately, there are chances that after adding these new features or bug fixes in a component, the developer might have involuntarily influenced the other parts of the system as well, and that could lead to damaging the existing functionality.

In order to prevent this damage or rather, new bugs, testers have to re-evaluate the performance of the entire product after any code change. Otherwise, these bugs could go  unnoticed, and it would lead to defect leakage as well as imagine the situation if these are caught in UAT or by a customer.

Now, retesting the entire system whenever a new feature or a bug fix is implemented can be tedious, time-consuming, and a very monotonous process, and in some agile projects, the need to run regression tests is often on a daily basis. So to cope with this demand and speed up the process, Automated Regression Tests are carried out with the help of testing tools that basically runs pre-written test cases with little or no human intervention.

Regression Testing

Source

Automated regression test cases need to be performed several times to identify problems with any new build. Repetition of these steps ensures that every area of the product has been thoroughly validated and the functionality overall is working as expected.

What is the difference between Regression Testing and Retesting?

Regression Testing is performed to ensure that any new changes made to the code do not have an adverse effect on the existing functionality application. Retesting, on the other hand, is performed when an issue is identified in an application and after the fix has been delivered, to ensure that the issue has been successfully fixed and is working fine. 

Let’s take a glance over the major differences between Regression Testing and Retesting.

          Regression Testing                          Retesting
Regression Testing is a type of software testing carried out in order to ensure that a recent code change has not impacted the existing functionalities adversely.Retesting is used to ensure that the test cases that used to previously fail have actually been fixed.
In Regression Testing, existing issues are not verified.In Retesting, verification of existing issues is carried out to assess the failed test cases.
Regression testing determines the possibility if there could be any unanticipated negative effects.Retesting ensures that the original problem which was found has been corrected.
Regression testing is done to catch new bugs if any in the software.Retesting is done to fix existing bugs in the software.

What is the need for Automated Regression Tests?

In this section, let us look at why automating regression tests are necessary.

  • Repeatability: In a strict agile project, regression tests need to be conducted in a highly repeated manner. If it’s done manually, the testing process takes a lot of time, as the number of test cases grows with time. Automated tests, however, can help in getting them covered even if the tests need to be triggered on a daily basis and would be much more efficient. 
  • No Human Intervention: Once the test cases are automated, there is absolutely no human intervention required while they are running. One can schedule them or trigger them whenever needed and come back to the results once they are completed. Also, this way, testing is going on 24*7 without any human support.
  • Lesser turnaround time: Manual testing can never match the pace of automated tests as and when the number of test cases grows. Automated Regression tests can be much faster and would be able to certify a new build in some hours of time when manual testing would take days to cover.
  • Increased Coverage: With automated tests, you can cover the same set of test cases in less time over different combinations of browsers and OS. With automation tools like BrowserStack, you can cover our regression test suite simultaneously over multiple combinations of devices, OS, and browsers in no time. You can get detailed analysis reports once the tests are completed, and they are thorough enough to discover any underlying issues. 
  • Efficient: Humans can be very error prone when it comes to repeating the same task over and over again. However, there is no chance of errors in Automated Regression tests; hence, you would see much better results.

Which tools can be used for Automating Regression Tests?

There are a lot of tools that help in automating regression tests. These tools help in framing the test scripts, running or scheduling them using CI/CD tools, and finally in getting reports of the test executions. These tools also increase the pace of executing the scripts through parallelism and, thus, improve the overall efficiency. 

Some of the popular tools that are widely being used are

  • Selenium: Selenium is an open-source project that provides a range of tools and libraries in order to support browser automation. It supports a lot of scripting languages like PHP, Java, Ruby, C++, JS, etc. It can easily be integrated with popular frameworks like Maven, Ant, etc. 
  • Appium: Appium is another open-source tool for running automation scripts and testing native, mobile-web, as well as hybrid applications on Android or iOS using a web driver. There are two versions available for Appium. One is a Node.js-based tool and the second is a desktop tool, however, both are used for mobile regression test automation. 
  • REST Assured: REST Assured is a framework that is built for REST service validation in Java and uses Java Libraries. In Rest Assured, the Java library acts like a headless client to act upon the Rest web services, and they are also capable of validating the HTTP responses from the server. The tool helps in improving the quality and maintainability of tests.
  • TestNG: TestNG is inspired by JUnit and NUnit. TestNG has been designed in such a way that it covers a wider range of test categories: unit, functional, integration as well as end-to-end, with easy-to-use functionalities.

Also Read: JUnit Vs TestNG

  • Maven: Maven is an automation tool that is used primarily for Java projects. It can also manage scripts written in C#, Ruby, Scala, and other languages. 
  • Jenkins: Jenkins is an open-source automation server. It helps in automating the parts of software development that are related to building, testing, and deploying. Jenkins facilitates continuous integration and continuous delivery.
  • BrowserStack: BrowserStack is a cloud web and mobile testing platform that provides the ability to test websites and mobile applications across on-demand browsers, operating systems, and real mobile devices. You can access 3000+ different devices and browser versions.  You can run Selenium, Cypress, Playwright,  Puppeteer, Appium, Espresso, and XCUI tests seamlessly using BrowserStack. It also offers integration with popular CI CD tools like Jenkins, Team City, Circle CI, etc.

Run Automated Regression Tests for Free

And the list is very long. All of these tools can be used individually or can be even used in combination in order to leverage the maximum benefit. For example, you can design a TestNG framework and write UI test cases using Selenium, run them over multiple browsers and device combinations through BrowserStack, and finally schedule all these test cases in a Regression Suite through Jenkins.

How to automate Regression Tests?

Regression Testing is a multi-layered process and can get very complicated for newcomers. Here’s a step-by-step guide on getting started with automated regression tests. A Regression Testing strategy would typically look like this:

  • Understand the requirement: This is the most crucial step where you need to understand what kind of tests are best suitable for our product, whether it should be the front end or back end, or both.
  • Picking up the test tool: Once you have the requirement underlined, you can choose the most suitable tool for achieving the same. For example, if it’s the front end, you can go for Selenium, or if it’s the back end, you can make use of Rest Assured
  • Figure Out The Cases That need to be automated: The next step is to figure out the list of cases that need to be automated as P0s or P1s. Once they are done, you can continue adding P2s and the remaining scenarios.
  • Automate test cases: The next step is to start automating the test cases that were identified using the framework designed.
  • Execute the automated test cases: Once the cases are automated, it is essential for us to run them locally and see if there are no false failures. False failures can lead to causing unnecessary alarms, and hence, they must be fixed at an earlier stage itself.
  • Preparing Regression Suite: Once the cases are automated and stable enough, you need to start adding them over in a Regression Suite. You can categorize suites like Smoke, Sanity, Regression, etc.
  • Reporting: Once the cases are automated and added to regression or smoke suites, you need to integrate a reporting mechanism which can help in sharing the run results once they are completed
  • Running The Test Suites Through Any CI/CD Tools: Once all the above steps are completed, you can choose any suitable CI/CD tool and get these suites scheduled to run on a daily basis or whenever a new build is promoted to the QA environments.

Best practices while automating Regression Tests

Now that you have come to an end before you close on Automated Regression Tests, let’s take a quick look at some of the best practices that you must follow. These will help us in making the tests robust and would help us in longer runs.

  • Update Regression Test Cases Regularly: The Regression tests should always be updated on a regular basis to ensure that the test suite is up to date with the most recent changes introduced in the application.
  • Categorizing Tests: It is necessary to categorize the regression tests according to the behavior of the application. This is because, later, when a test fails, you will know which category the test falls in and you would be able to easily analyze that area of the application and provide necessary information to the developer Team.
  • Re-Run Successful Test Cases: In an agile world, it is critical to re-run even the successful test cases over and over again to ensure that the application continues to function properly.
  • Pay Attention to the Test Reports: Even if the regression tests are being carried out on a daily basis, you must dedicate some time and analyze the reports properly. This way, you won’t miss even any minor bugs.

Running Automated Regression Test with Selenium and BrowserStack

Now that you have learned enough about automating Regression Tests, let’s see how you can frame a sample test script and use it for Regression Testing.

For this example, let us automate a UI scenario using Selenium with the TestNG framework. While Selenium will provide us with all the methods to perform the UI operations, TestNG will help us maintain the tests using different annotations, @BeforeTest, @AfterTest, etc.

Along with Selenium and TestNG, you are also making use of BrowserStack here for maintaining our Selenium Grid and the browser infrastructure. You must be wondering why. 

When it comes to Regression Testing, with time, as the number of cases and the platforms or browsers increase on which the product needs to be certified, it becomes tough to maintain the infrastructure behind running those multiple devices, browsers, and OS. As and when the number of test cases increases, it becomes even more difficult to scale it over with devices capable of supporting a lot of multiple threads.

In such cases, you can leverage BrowserStack’S capabilities. BrowserStack enables developers and testers to test their websites and mobile applications across 3000 + real browsers, operating systems, desktop, and mobile devices. This is possible for users having to install or maintain an internal lab of virtual machines, devices, or emulators. 

For example, in a simple UI Regression Suite, with BrowserStack, you can run your cases in multiple threads over a cloud Selenium Grid with your choice of OS, Browser, and Browser Version.

So, let’s learn to frame our first automation script with BrowserStack. Login to BrowserStack Automate.

In the example shared below, you have framed the Selenium Grid details and the browser capabilities in the BeforeTest method.

class FirstTestWithSeleniumGrid {


    public String username = "#YOUR USERNAME#";

    public String accesskey = "#YOUR ACCESSKEY#";

    public static RemoteWebDriver driver = null;

    public String gridURL = "@hub-cloud.browserstack.com/wd/hub";

    @BeforeTest
    public void setUp() throws Exception {
        DesiredCapabilities capabilities = new DesiredCapabilities();
        capabilities.setCapability("browserName", "chrome");
        capabilities.setCapability("version", "102.0");
        capabilities.setCapability("platform", "WINDOWS");
        capabilities.setCapability("name", "FirstTestWithSeleniumGrid");
        try {
            driver = new RemoteWebDriver(new URL("https://" + username + ":" + accesskey + gridURL), capabilities);
        } catch (MalformedURLException e) {
            System.out.println("Invalid grid URL");
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }


    @Test
    public void learnFirstTestUsingSeleniumAndBrowserStack() {
        try {
            driver.get("http://www.google.com");
//Locating the search box of google
            WebElement element = driver.findElement(By.name("q"));
// Sending browserstack keyword for search
            element.sendKeys("BrowserStack");
            element.submit();
// Locating the browser stack option and clicking on it
            WebElement browserStackLink= driver.findElement(By.xpath("//a[@href='https://www.browserstack.com/']"));
            browserStackLink.click();
            Thread.sleep(1000);
//Printing the title of the opened web page
            System.out.println(driver.getTitle());

        } catch (Exception e) {

        }

    }

    @AfterTest

    public void closeBrowser() {

        driver.quit();

    }

}

Once you run the test case, you will see the below console output.

Console Output

You can switch to the Browser Stack dashboard next and check all the test details as shown below.

Browser Stack dashboard

You can play the test that has been performed or even download the test case. Browserstack provides a wide range of capabilities that detail every step in detail, along with the time of execution.

Try BrowserStack now.

Regression Testing plays a vital role in any software development lifecycle, and automated regression testing is the only way ahead to leverage the maximum benefits of regression testing. Plus in order to cope with ever-increasing user demands and frequent releases, you must adopt automated regression tests in order to ensure faster turnaround and an efficient, bug-free product.

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Automation Testing

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