By Due to the massive advancements in the modern software development industry, it has become a critical component to ensure the visual integrity of web applications across different browsers and devices. Visual testing automation is a component of automation testing that automatically detects visual regressions and user interface inconsistencies early in the development cycle.
Therefore, using automated visual testing, testers can ensure a seamless user experience. On the other hand, Playwright is Microsoft’s open-source automation library. Using this tool, the developers can access powerful capabilities for automating the visual test cases. It also has various other parameters that massively help to boost the accuracy and dependability of the automated test cases.
With this article, we will understand some of the fundamentals of visual automation testing with Playwright. We will also understand some of the major benefits of automating the visual test cases with Playwright. Finally, we will conclude our discussion by understanding some of the major practices that the developers can integrate to utilize the full potential of this process.
Understanding Automated Visual Testing
Visual automation testing is the process of capturing screenshots of web pages and comparing them against baseline images. The main objective of this process is to identify any differences in styling, content, or layout.
In this context, we would mention that traditional functional testing focuses on verifying the behavior of web elements. However visual testing ensures that the visual aspects of the application remain consistent across devices and environments.
The developers can mostly utilize the full potential of visual testing in the following aspects:
- Detecting visual regressions that might be initiated by code changes or upgrades to third-party libraries or dependencies.
- Verifying the responsive design across various screen sizes and devices.
- Validating the accuracy of CSS styles and layout positioning within the web app.
So, by using automated visual testing the app testing teams can streamline the testing process, deliver high-quality web apps with confidence, and reduce the overall manual effort.
Introducing Playwright
Playwright is a powerful automation library that allows testers to automate interactions with popular web browsers like Mozilla Firefox, Chromium, and WebKit. This tool is developed and continuously maintained by Microsoft. Playwright also offers a unified API for automating the browser instances and enables the developers to write browser tests using multiple programming languages like JavaScript, Python, and many others.
Let us now shift our focus toward the key features of Playwright for executing automation testing:
- Cross-Browser Compatibility
Playwright provides native support for multiple browser engines including Firefox, Chrome, and Safari. This support allows the teams to test web applications across different browsers and browser versions easily.
- Headless and Headful Test Execution
While using Playwright, the testers can either initiate the browser instances in a headless or headful format. It is worth mentioning that headless browsers refer to those browser instances where the graphical user interface is not initiated. The primary goal of this process is to reduce the resource consumption and improve the overall testing efficiency.
- Rich Automation Capabilities
While using Playwright, the testers can access comprehensive automation capabilities which include element interaction, page navigation, file uploads, and many more.
- Integrated Visual Testing
Playwright provides native support for visual testing. This addition allows the developers and testers to capture screenshots and perform image comparisons very easily.
In short, the rich feature set and robust architecture of Playwright simplify the process of automating browser-based test cases including automated visual testing.
Beginner’s Guide for Automating Visual Test Cases with Playwright
Now, it is time to understand the basic setup process of visual automation testing with Playwright. To simplify this knowledge for the new visual testers and developers, we have added all the required steps in the required chronological order:
- Step 1: The Installation Process
The developers have to begin the process by installing Playwright using npm (Node.js package installer). In this regard, we would like to advise the testers to download the required tools, dependencies, and plugins from official websites to avoid any malicious attacks or privacy concerns.
By entering the following code in the terminal window, the testers can install Playwright into the testing environment:
npm install playwright
Alternatively, the developers can also enter the following command to perform the installation process using Yarn:
yarn add playwright
- Step 2: Writing The Visual Automation Test Script
The next step in this process involves writing the test cases for executing visual testing on the web applications. This process will begin by creating a new test file and naming it as per the test requirements. After this, the testers have to import the necessary modules by integrating the following command in the terminal window:
const { chromium } = require(‘playwright’);
To explain the test case creation process, we have used the example of writing a simple test that navigates to a web page, captures a screenshot, and saves the file into the disk:
- Step 3: Executing the Test Cases
Now that we have finished installing Playwright in the testing environment and also created the required test case, it is time to begin the test case execution process using node.JS. The testers simply have to enter the following command in the terminal window to begin the execution process:
node visual-test.js
After this command, Playwright will launch the Chromium browser and navigate to the specified URL mentioned in the test script. Then, as per the test capabilities, it will capture a screenshot and save it as ‘screenshot.png’ in the current directory within the system.
- Step 4: Executing Visual Regression Testing
The final step in this process is to conduct visual regression testing. For this process, the testers have to capture a baseline screenshot and compare it against subsequent screenshots to detect any visual differences present within the application user interface. It is also advisable to use various tools like Jest or the native Playwright screenshot comparison feature for this purpose.
Advantages of Automating Visual Test Cases with Playwright
Now that we have finished discussing the process of executing automated visual regression testing using Playwright, let us go through some of the major features that justify the integration of this advanced testing process with the application development and testing life cycle:
- Early Detection of Visual Defects
By integrating automation testing with visual testing, the application development and testing teams can detect user interface errors and styling issues at earlier phases of the development cycle. This approach will prevent them from reaching production or turning into a serious concern.
In this context, we would advise the app developing companies to integrate Agile methodologies like continuous deployment and continuous integration to further improve the efficiency of the automated visual regression test cases. Using this approach, it is possible to execute the development and testing phases simultaneously to detect and remove errors as soon as they appear in the source code.
- Improving the Overall Test Coverage
By executing visual testing, the testers can ensure a comprehensive coverage of the user interface including multiple elements like styling, layout, and content. It also ensures that there is at least one dedicated test instance for verifying the performance of all the elements within the application interface. Moreover, it is possible to guarantee this integration across multiple browser and device combinations.
- Integrating Cross-Browser Testing
As we have already mentioned earlier, the testers need to verify the stability of the application interface across multiple browsers, operating systems, and devices. So, by integrating cross-browser testing, it is possible to execute this process by running the test instance on different devices and software combinations simultaneously.
Moreover, the testers can also use AI-powered test orchestration and execution platforms like LambdaTest for executing automated cross-browser testing on thousands of devices and browsers through remote servers. These servers also have access to outdated browser versions and legacy devices.
LambdaTest can also execute the automated Playwright visual test cases on more than 50 browsers at the same time. Some of the additional features of integrating cloud platforms include improved troubleshooting with comprehensive test reports and improved test reporting using live activity logs.
- Streamlining The Testing Phase
By utilizing Playwright’s unified API and integrated visual testing capabilities, the testers can simplify the process of writing and executing the browser test cases. This approach also helps to reduce manual effort and improve productivity. Moreover, by integrating automation testing with visual test cases, the developers can also eliminate the possibility of errors that can happen due to human intervention.
- Improving the Visual Scalability
Since the modern application development industry and the requirements of the end users are constantly evolving, app developers and testers need to keep up with these changing requirements. Based on these, they need to roll out subsequent updates to the application to fix existing errors or add new features.
These changes to the user interface of the application can harm the functioning of the existing elements and can even crash it in a worst-case scenario. By integrating automatic visual regression testing, the testers can ensure that the test cases are automatically triggered when there is any change in the source code. This will help verify the app’s stability and continuously boost its scalability.
- Enhancing the Team Collaboration
While executing automated visual testing, the application developing companies can achieve common ground for developers, designers, and quality assurance engineers. Using this ground, they can collaborate and ensure consistent visual quality across multiple web applications. Moreover, while executing visual testing, the non-technical members of the app company can also collaborate with the development and testing teams.
So, by using Playwright for executing visual automation testing, the application developing teams can deliver visually polished and user-friendly web apps. The proper execution of automated visual testing also helps to improve the confidence and efficiency of the testing teams.
By verifying the proper placement and functioning of the UI elements, it is possible to guarantee the application stability which in turn will help to improve the company’s business and build a positive reputation.
The Bottom Line
Conclusively, visual automation testing has a pivotal role in ensuring the visual integrity and user experience of web apps. Using Playwright, testers can automate browser-based test cases including visual testing with efficiency and ease. By detecting the visual regressions at the early stages of the testing cycle, the testers can ensure a consistent user interface across different environments.
The integration of visual testing and automation testing also helps the teams to deliver high-quality web apps that meet user expectations. So, by embracing visual automation testing with Playwright, the app developing companies can streamline the testing process and also elevate the quality of the web applications.