What is Front-end Testing? Tools & Frameworks

Front-end Testing

Front end testing is an approach or a technique in which we test the GUI (graphical user interface), functionalities and usage of a web application or a software. The aim of performing front end testing is to test all the functionalities in order to ensure that the presentation layer of the application or software under testing is free of defects or bugs.

Consider, you enter your details into the frontend of a web application, however numbers should not be accepted. Another similar example would be to check the alignment of the graphical user interface (GUI) elements.

Front end testing is performed −

  • For CSS regression testing: Minor changes in CSS that breaks the layout of the frontend of a web application or software.

  • To Make changes in JavaScript files to make the frontend non-functional.

  • To check the performance of the web application or software.

In front-end testing, we check the GUI (graphical user interface) of the web application to make sure it is error-free. Moreover, we must check all the elements, such as buttons, labels, drop-down behaviour, etc.

Types of Front-end Testing

Developers make the software product consistent and stable but cannot do so without the help of testers. Front-end testing includes a variety of strategies. It includes practices that were prevalent in back-end development for years. A test strategy has to be compatible with the codebase.

  • Unit Testing  − Code is constituted of units, where each unit is the smallest part of the software that can be tested. We require each and every bit to function well and independently. Unit testing is the lowest level of software testing in which we test the individual components of the software or application under testing. In unit testing, there are one or more inputs and in general a single output. Unit testing helps us make sure that the code works as expected before developing any feature. Unit testing involves calculations and input validations.

  • Acceptance Testing − Here, we test the acceptability aspect of a system or software. We check whether the software or system meets the business requirements. Then, we test whether it is completely ready for release to end-users or not. Suppose, while building a Lego house, we check whether all the pieces are perfect or not. All this is covered by unit testing. Next, we ensure that all the instructions are followed. To do that, we check the Lego house after completing each stage or floor of its. Acceptance testing checks the running application to make sure that the user flows, user inputs, and designated actions are functioning properly.

  • Visual Regression Testing − While making a change in an application, there is always some risk that the existing feature may break. That is where regression testing is required. Visual regression testing is a sub-category of regression testing that is related to the user interface (UI). Intakes UI screenshots and compare them with the previous ones. We take the previous screenshots from the live site or baseline. This testing is unique for the front-end of an application or software. We use image comparison tools to find the differences between the two screenshots.

  • Accessibility Testing − This testing ensures that we can access the application or software easily and simply. This involves users over a particular age (say 18) and those with disabilities. It involves checking whether the application or software is compatible with devices, e.g., screen reader.

  • Performance Testing − The performance of any website or application is of extreme importance. Performance testing helps us check the stability, responsiveness, and speed of the application or software. It checks how the application behaves in various scenarios. Most of the tools for performance testing are plug-and-play, while some offer an option to customize the execution of tests.

  • End-to-end Testing − The flow of the application or software under testing must be as smooth as possible right from the beginning to the end. The end-to-end testing helps us make sure that its behaviour meets the expectations throughout its running. End-to-end testing maintains data integrity between systems and its components. It also discovers the system dependencies and helps the testers fix the system-related or setup-related issues.

  • Integration Testing − It combines various units and tests them in a group. The single units function well generally, however after integration, they may not interact so smoothly. E.g., after integrating the drop-down list of a website into the navigation bar, it might stop functioning. However, integration testing finds all types of defects that arise after merging the codes. Test stubs along with test drivers smoothen integration testing.

  • Cross-browser Compatibility Testing − Cross-browser testing is the most important type of front-end testing. It emphasizes on enabling the users to have the same experience with various browsers. A function available on one browser must be available on the other one too. Cross-browser testing helps us make sure that the application or software under testing functions properly on different operating systems, devices, and browsers.

Creating a frontend website testing plan

Follow the steps below to create a front-end testing plan −

  • Decide the tools you will need to manage your test plan.

  • Create a budget for the front-end testing.

  • Define the deadline of the project.

  • Define the scope of the project. The scope includes −

    • Operating Systems and browsers

    • Popular devices

    • Audience proficiency

    • Correction in the internet speed of the audience.

Importance of front-end test plan

A front-end testing plan helps us decide upon the browsers and operating systems that the project has to cover. There are many combinations of browsers and operating systems that could be tested on the front end. Moreover, a testing plan saves our testing effort and money. Front end testing plan helps us clearly understand the scope of the project and boosts confidence in project deployment.

Tips for front-end testing plan

  • Draw the budget, prepare the resources and the deadline judiciously.

  • To perform the test cases faster, use a headless browser.

  • Reduce the number of Document Object Model (DOM) rendering in test cases to speed up execution.

  • Reuse the test scripts to speed up regression cycles.

  • Give consistent names to your test scripts.

Tools for front-end testing

  • LambdaTest − It is the most commonly used tool for cross-browser testing and helps more than 1,00,000 users every year. It provides a scalable, secure, and reliable cloud-based Selenium grid on more than 2000 browsers and browser versions to perform automated web application testing and to maximize the test coverage.

  • Jasmine − This behavior-driven development framework is used to test the JS (JavaScript) code. Jasmine emphasizes business values more than the technical details. Its syntax is so clear that we can write tests with much ease. It is not dependent on any other JS framework. However, Jasmine is impacted by unit testing frameworks, e.g., JSSpec, ScrewUnit, JSpec, Rspec, etc.

  • Selenium − This tool is used for front-end testing as well as functional testing. It enables end-to-end testing across multiple browsers and OS. It also helps write test cases in different programming languages, e.g., JAVA, PHP, C#, etc. Selenium provides record and playback features to create test cases.

  • Needle: − This front-end testing tool is used to test CSS. Needle evaluates the visual elements, e.g., font/CSS/images by taking screenshots of particular parts of the website or application under testing. It enables us to calculate CSS values and the position of HTML elements.

Automated testing requires a lot of effort in the preliminary stage. Thus, front-end testing needs more time and effort. The front-end testing tools may face some compatibility issues with OS and browsers.

Front-end Performance Optimization

Front-end performance testing determines how quickly the web page loads. It is always a good practice to optimize the front-end performance for one user before testing with massive user loads.

Importance of Front-end Performance Optimization

Earlier, by performance optimization, we meant improving the server-side of the application or software as back then most of the websites were static and the processing was mostly performed on the server-side.

With the introduction of Web 2.0 technologies, web apps and other software became more dynamic and less static. Eventually, the software code on the client-side became more of a performance hog.

Advantage of front-end performance optimization

  • Discovering the server bottlenecks is important in website testing, however, detecting the client-side performance issues is equally important because they affect users’ experience.

  • By enhancing the back-end performance by around 50%, we can improve the overall performance by 10%. While enhancing the front-end performance by 50%, we can improve the overall performance by around 40%.

  • Front-end performance optimization is simple and cost-effective.

Front-end Performance Testing Tools

Page Speed − This is an open-source tool from Google used for performance testing. It checks web pages and gives advices to reduce the loading time of the web pages. It fastens the retrieval of web pages while accessing web pages through the Google search engine.

YSlow − This tool is used for testing the front-end web performance. It checks the performance of the web pages by evaluating all the components on the page, including those made by using JavaScript. YSlow measures the performance of web pages and gives suggestions.