Automated Visual Regression Testing on Cloud for Beginners

Introduction

Regression testing has been a significant shield in exploring early bugs and not letting any new changes disrupt the already existing state of an application. Considering the highly complex applications with the number of lines of code extending to millions sometimes, there is no way we can determine what change could show its effect and at which part of the code.

One form of this process is visual regression testing, where we ensure that the look and feel of the website or app is not affected in any release iteration. While it’s not a new concept, it has gained a lot of prominence in recent years. As digital experiences are becoming more and more important, visual quality has become an important quality parameter as well. This could be because if the website doesn’t look good, it won’t sell either.

However, from a technical perspective, let’s see what visual regression testing is and how it shapes the automation testing world with the help of automated visual regression testing tools.

What is Visual Regression Testing?

Regression testing certainly has no boundaries or restrictions for including test cases. One of its subdomains is visual regression testing, which applies the same process but to visual elements. So, what comes under visual elements? Everything you see on a web page is a contender to be included in the visual regression testing.

Regression testing of visual elements verifies whether the changes done in the present release are consistent with the previous release. This means the elements intended to be at the same place with the same coordinates should remain in this release. There are several use cases where we need visual regression testing. For instance:

• When the device we test differs from the device a user is operating, the rescaling of the application may impact the pixel position.
• It helps maintain the consistency of the application across any platform.
• It helps explore the rendering issues of the application.
• It helps explore issues based on a responsive characteristic of the website.
• Fonts and color issues are also explored when visual testing is performed.

Visual regression testing also connects to other testing phases that work through the UI elements. For example, if the elements are perfectly aligned, we can expect the modals to pop up at the correct place or keyboard and mouse events to act accordingly.

How to Perform Visual Regression Testing?

Visual regression testing can be performed in two ways:

• Manual
• Automated

Manual Visual Regression Testing

The manual regression testing of visual elements has been in place since the inception of web application development. In earlier times, when we made a change, we first manually and visually checked how it looked on the web page.

However, it was done only on a single system, which generally used to be the local development system. As technology evolved, so did the elements on the page. Today, for serious web businesses that have hundreds if not thousands of web pages, manual visual regression testing is pretty time consuming. Though it’s still possible, and is really great for finding issues, it is not accurate for bulk testing.

Automated Visual Regression Testing

The problem with manual visual regression testing is that the human eye cannot detect changes as minor as a couple of pixels. While in many cases, a single pixel change may not be a concern, in many other cases, it might be. As a tester, we cannot take such risks, and therefore, when it comes to visual testing, we should (and must) always turn towards automated visual regression testing.

Automated visual regression testing lets the computer take over and compare the current version of the webpage with an ideal version through automation scripts. This ideal version could be a design file, or an earlier perfected version of the webpage. Since computers go pixel by pixel, they can help ensure that the new version does not deviate much from the ideal version.

One of the biggest challenges in this approach is how to take into account the large fragmentation of devices that are available today. The overlapping of the ideal and previous versions should happen on each device with definite specifications. This demands a heavy budget to procure these devices, build an infrastructure, run it, maintain it, and hire a team to do this task. Obviously, only a few organizations can finance this budget easily, knowing that the operation might not succeed. A more efficient and cost effective method is to turn toward cloud solutions with a robust infrastructure already in place, such as LambdaTest.

How to Automate Visual Regression Testing on the Cloud?

When we migrate from on-premise infrastructure to a cloud based one, we see some significant benefits because of this shift. The most useful of them are minimized maintenance and no overheads of setup optimization. Moreover, you are not restricted to local systems save a ton of money on device procurements, which never stop as they are released frequently in the market.

We have two options to use cloud infrastructure for automated visual regression testing. Either build a cloud infrastructure or rent out one from organizations already excelling.

Building our infrastructure will incur even more costs, which were our primary major concern anyway. On top of it, when we build our cloud infrastructure, we do not eliminate most of the problems we face with the on-premise infrastructure, except for the convenience of scaling up easily. We still need a big team to manage the infrastructure. We still need to purchase devices. We still need to maintain the infrastructure, etc.

Renting out an existing managed cloud infrastructure eliminates all the issues and brings down a lot of the costs significantly. We pay only for the time we use the infrastructure and do not have to spend time and resources in maintenance and scale.This is efficient, feasible, and the best automated visual regression testing option. To demonstrate how such tools work, let’s take the example of LambdaTest.

LambdaTest is an AI-powered test orchestration and execution platform that helps you perform manual and automation testing at scale, including automated visual regression testing. It provides over 3000+ browsers and OS ready to test your web pages instantly.

To perform visual regression testing on LambdaTest, follow the below steps:

1. Sign up on the LambdaTest platform.
2. Once you are in the user Dashboard, navigate to SmartUI from the left menu.

   

   

3. Click on New Project.
4. Choose the platform as Web for running your automated tests. Provide project-specific details like Project Name, Add Approver(s), and Add Tags.

   

5. Click on Create Project to create your SmartUI Project.

   

6. Select the testing framework from the available options like Selenium, Cypress, Playwright, etc.

   

7. It will guide you to a screen with instructions to set up and configure your tests.

   

8. Clone the sample LambdaTest GitHub repository for SmartUI.
   Shell

   git clone https://github.com/LambdaTest/smartui-node-sample

9. Set up your LambdaTest credentials (Username and Access Key) as environment variables.

   macOS/Linux:

   Shell

   export LT_USERNAME=johnd
   export LT_ACCESS_KEY=abacbcbafaaabffkiifgghhjvgxhgsagccb

   Windows:

   BAT

   set LT_USERNAME=johnd
   set LT_ACCESS_KEY=abacbcbafaaabffkiifgghhjvgxhgsagccb

10. Configure the LambdaTest desired capabilities in your test script.
    JavaScript

    let capabilities = {
        platform: "Windows 10",    // Configure your OS for Selenium test
        browserName: "chrome",     // Configure your Browser for Selenium test
        version: "latest",         // Configure your Browser Version for Selenium test
        visual: true,              // Configure your Capture screenshot  for Selenium test
        name: "test session",      // name of the test for Selenium
        build: "Automation Build", // name of the build for Selenium
        "smartUI.project": "<Your Project Name>", // Replace the name of project 
                                                  // with the new project name
        "smartUI.build": "<Your Build Name>",     // Replace the name of Build 
                                                  // with the new Build name
        "smartUI.baseline": false,                // Enable if you want to update 
                                                  // to a new baseline build
      };
     
      // Connecting to the Lambdatest Selenium Cloud Grid with Smart UI
      let gridUrl =
        "https://" +
        "<Your Username>" +
        ":" +
        "<Your Access Key>" +
        `hub.lambdatest.com/wd/hub`;
     
      // Here is your Remote WebDrive Connection
      let driver = await new webdriver.Builder()
        .usingServer(gridUrl)
        .withCapabilities(capabilities)
        .build();

11. Add a SmartUI Webhook to your test cases, as shown below.
    JavaScript

    driver.executeScript(`smartui.takeScreenshot,{screenshotName:<Name of your Screenshot>}`)

12. After that, you can test the run command to execute the test.
    Shell

    npm i && node test.js

13. To view your test results, navigate to LambdaTest SmartUI Dashboard.

Along with visual regression testing, LambdaTest aims to provide the tester with a complete experience where they don’t have to deviate to other platforms for different testing needs. The tester will get the following features as well when he signs up for the platform:

Live Interaction

Along with testing the match of pixels for different web pages, you may also need to operate the device just like an end-user. This can be achieved through live interaction where the tester can use real devices to upload their application installer file and use the application on the platform of their choice.

A similar process is followed for the web application as well. Through live testing, we get a feel of the functionalities offered by the application and explore GUI-related bugs that are hard to catch in automation testing.

Geo-Location Testing

Organizations looking to release their application beyond their country’s boundaries must respect the laws of the country the end-user resides in. While VPN may work in such scenarios, it is extremely slow and provides wrong parameter metric values.

The other option of hiring a freelance tester from that country is unsecured and expensive. For such requirements, LambdaTest provides geolocation testing methods. With this, the tester can change the end user's country with a simple scroll button.

The application will now be seen as it would be in the selected country. The testers can explore the application here and test for legal compatibility or platform-specific requirements for that particular country.

Security

Security is extremely important as sensitive data is involved, and the Internet is vulnerable to attacks. This becomes an additional overhead when on-premise infrastructures are set up. However, LambdaTest prioritizes security by creating a secure tunnel between the tester system and the cloud machines. It comes with SOC Type 2 certification and is GDPR compliant so that testers do not worry about security and can focus completely on their work.

Integrations

Third-party integrations complete the testing process by providing additional functionalities and automating them through integrations with the framework. For a cloud-based tool, this becomes important as no testing process is complete solely by scripting and visual regression tools.

Once visual regression (or any other testing) is done, you can share the bug and its details, create a ticket, file a bug, document it in the report, and so on. All this can be achieved through integrations, and when they are not available, moving back and forth tens of times a day becomes annoying and error-prone as well.

LambdaTest has hundreds of integrations covering all the major tools and frameworks a tester would want to show off his skills. Testing on the platform helps you gain more focus as tools are connected, and all the data is centralized in a single place.

AI-Powered

Artificial intelligence is adopted in a lot of technologies today. It optimizes a lot of tasks, including automation, which reduces the time of test completion. LambdaTest adopts this technology to reduce the testing time by up to 70%.

This shows a huge impact on other software development cycles and the project costs as well. Termed “HyperExecute”, this can combine reports and logs from various resources to provide a combined logical log (and report) for further analysis. Testers can take this one step further by integrating over the cloud, such as AWS or CI pipelines, according to their requirements.

Logging and Reporting

Finally, a good cloud-based tool is expected to have logging and reporting capabilities to analyze our work and plan for the future. This feature is divided into two parts; logging and reporting.

Logging documents most of the actions in a log file that generally resides on the machine where testing is executed. The major benefit of logging the actions is to trace the errors without executing the failed test again. It also gives insights into the user's actions and helps derive multiple patterns.

Reporting, on the other hand, is the final result of the testing phase. It contains the results of testing in pictorial and written form. Reports also contain information such as tools used, the platform used, the time it took for test execution, and other relevant information. This is, however, just a small brief into the world of reporting and logging. These invaluable resources today hold deeper meaning than just a couple of benefits.

Nevertheless, their importance makes them necessary to be included in our framework. LambdaTest eliminates this process because a lot of the time, a tester may have his favorite framework that may not support reporting. Or even if it does, it would be in a very vague form.

Hence, LambdaTest provides its reporting features with a dedicated team working to improve it continuously. A tester can expect everything important to be in the report with a facility to store them in your account for retrospect.

Conclusion

Visual regression testing is necessary where first impressions may mean real business and value. While users expect their application to always be in its top form, the responsibility of testers grows with these expectations.

With many options available today, cloud-based automated visual regression testing methods are the most efficient. They provide automation support, visual regression support, support for integrations, reporting, and even AI-powered elements. This fulfills our requirements and helps wrap things faster, which is a win-win for everyone involved, from production to release to the end-users.