Understanding The Importance of Visual Regression Testing

Understanding The Importance of Visual Regression Testing

Every software developer wants his app to be accepted by users and give good reviews that will boost brand reputation. But during these highly competitive times, with millions of apps released every year, many get rejected due to mediocre quality. In fact, Statista says there were already around 29,000 mobile apps released in September 2024 through Google Play Store. So, if you want to stand above the crowd and want users to accept your app, ensuring it aligns with user expectations through reliable testing methods cannot be overlooked. Users are non-forgiving when it comes to mediocre apps with flaws in functionality and user experience.

One such testing technique that is indispensable in software testing is visual regression testing. This method, also called visual testing, verifies the usability and appearance of your application before release. Like regression testing, it is performed after any code changes made by the developer to verify that they have not affected the app’s visual interface. This article will reveal all the information you need to know about this testing method, such as its benefits and the different types available.

Knowing About Visual Regression Testing And Its Importance

Visual regression testing is a method that checks every visual and layout element to catch errors like improper alignments, overlapping modules, and missing or hidden elements.

Assume you are using an app to book a taxi to go to the airport, and you finally reach the checkout page after spending valuable minutes and entering lots of information. Then, you discover, to your frustration, that the checkout button is hidden, delaying your booking process. As a customer, you are unlikely to use the app again and may even post a negative review about it. This is exactly why visual regression testing should be a valuable part of your testing strategy,

Performing visual regression testing reduces the chance of bringing costly visual bugs into the production environment. If the visual elements of your app are not validated, then you are likely to end up losing your brand reputation and even make losses in the long run due to reduced customers.

Why Visual Regression Testing Is Important

These are the three key reasons why visual testing should never be missed while developing software:

  1. Identifies unintended changes: It reduces the effect of code changes that may cause confusion to the application user.
  2. Maintains quality: Visual testing is important because it makes sure the functionality and the appearance of the app are consistent.
  3. Cost-effective: Visual regression testing, if done at the right time, avoids a lot of rework during the production stages, saving time and money.
  4. Cross-browser and cross-platform compatibility: It helps to ensure that your app’s UI works in the same way across different browsers, devices, and operating systems

How Visual Regression Works

These are the different stages in the visual regression process:

  1. Creation of baseline: First, UI snapshots are captured, and they are used as reference points when comparing subsequent versions.
  2. Test execution: Once there is an alteration in the code, new screenshots are captured during the test run.
  3. Comparing images: The visual testing tool compares the new screenshots with the baseline images to find the differences.
  4. Difference analysis: The changes are emphasized visually, and reports are generated to determine the areas where the changes have taken place.
  5. Review and corrective action: The identified differences are then evaluated by the development team to ensure that they are deliberate or not. These variations are resolved before the app is released to the market.

Techniques of Visual Regression

There are different methods by which you can conduct visual regression testing. Let us explore them one by one:

  1. Layout comparison: This technique involves comparing the size and position of various visual elements.
  2. DOM comparison: In this method, the user interface is verified by analyzing the HTML structure. This helps to detect layout inconsistencies and missing elements.
  3. Pixel-to-pixel comparison: It involves the comparison of the pixels of the UI before and after changes. It is mostly used for testing small, complex UI elements or those that are critical to the user experience. This method is accurate but time-consuming.
  4. Visual AI comparison: In this method, artificial intelligence is used to compare the design elements and functionality before and after UI changes. It is gaining popularity due to its greater accuracy and efficiency compared to traditional methods.
  5. Manual visual testing: A tester manually compares screenshots of the UI’s before and after changes. This is a time-consuming method and prone to errors, but it is suitable for testing specific UI elements or small projects.

Choosing The Right Method Between Manual And Automated Visual Regression Testing

Manual visual regression testing

As more features and functionalities keep getting added to an application, the scope of the testing process grows larger. It becomes essential for the manual tester to spend more time reviewing the screenshots to determine bugs. When there are strict deadlines, manual testing becomes impractical and expensive. Moreover, when different testers work together, there may be inconsistencies in test results due to the varying standards of each tester.

Automated visual regression testing

Contrarily, in automation testing, the process of checking the app after every code change becomes quicker and easier as it is automated. The automated visual testing process lets testers capture, compare, and detect even minor visual discrepancies between two images. Moreover, automated testing lets you repeat as many tests as needed and log and report defects without manual effort. In addition to saving time, it increases the efficiency and accuracy of the process. You can also integrate your automated tests into your CI/CD pipelines, improving the software quality during development cycles.

The final decision between manual and automated visual regression testing should be based on factors like the project’s scale, timeline, budget, and the criticality of the software’s appearance. For larger and more complex applications, automated testing is the best option, as visual consistency is a crucial factor.

Conclusion

Your application’s UI creates the first impression in the customers’ minds, and hence, visual testing in software development is a must, whether through automated techniques or a mix of manual and automated methods.

To ensure the highest level of precision, you must pick a visual testing tool that can point out even the smallest deviations in appearance and deliver a consistent, flawless user experience every time. With a thorough visual regression testing process, you can ensure your app’s success and a positive experience for your users.