Front End Testing: A Complete Guide for Beginners
Tags: frontendtesting, testgrid
Published: 2024-06-21 13:18:55

When you use any software, application, or website, the first thing you notice is its interface consisting of different visual elements, such as images, icons, text, etc. This is usually referred to as the front end, also known as the client side.

The front end encompasses everything visible to a user while navigating through a website and constitutes a crucial part of any application or website for end-user interaction.

However, before launching any application or website, it is crucial to ensure that all visual elements are correctly placed and function as intended. This is where the importance of front-end testing comes into play.

In this article, we aim to enlighten you on front end testing, its importance, its types, best practices.

## What is Front End Testing?

Front-end testing is a software testing type that assesses an application’s or website’s interface for its look and feel. It evaluates the graphical interface’s visual elements (icons, images, text, links, forms, menus, etc.) for their functionality. It checks whether all visual elements behave as per end users’ requirements and expectations. 
For example, front-end testing checks if: 

- The text field accepts only characters. 
- The email field accepts characters, symbols, and numbers. 
- The field to enter a contact number accepts only numbers. 
- The form gets submitted only after all the mandatory fields are filled. 
- The navigation is easy and clean. 
- A specific button is functioning correctly. 
- The page loading speed is fast enough and much more. 

In addition, front end testing checks the app’s or website’s compatibility across different browsers and devices. 

Every application or website architecture has three tiers – presentation, application, and data. Front end testing aims to evaluate the functionality of the presentation layer and ensure that it is free from bugs and errors. 
However, it is important to note that a testing team performs front-end testing after every update to an application or website. This ensures the recent updates do not affect the UI’s functionality and look. 

## How Does Front End Testing Differ From Back End Testing?

As we have discussed, front end testing evaluates an application’s user interface for its looks and functionality. Simply put, it verifies the app’s presentation layer is free from bugs and errors and functions as intended. 

Before moving to back end testing, let us understand what the back end is. 
The back end of any application or website is a part that makes it functional and is not visible to end users. It comprises different components, including data storage, business logic, databases, and server-side scripting. It is also referred to as the server side.  
Back end testing evaluates the functionality and correctness of back end components. It primarily focuses on testing an app’s or website’s business logic, performance, and security.

## The Need for Front End Testing
Here are some major reasons that state the importance of front end testing: 

### Identify Performance Issues
 
User experience is paramount when it comes to any software application or website. If users find any issues navigating through the app, they are more likely to stick to alternatives. 
Did you know that 85% of customers do not return to a website with a poor user experience? 
During development, developers primarily focus on the application and data layers rather than the presentation layer, which forms the foundation for any app or website. Hence, it becomes crucial for the QA team to test the presentation layer by keeping end users’ perspectives in mind. This helps uncover potential client-side performance issues that may degrade the user experience. 

### Verify the Cross-Browser and Cross-Device Compatibility
Validating the app’s or website’s functionality across a range of browsers (different versions) and devices is another reason for front-end testing. People use different kinds of devices (laptops, tablets, etc.) and browsers (Firefox, Safari, Google Chrome, etc.)
Therefore, it’s crucial to make sure that the app functions as intended across a range of hardware and web browsers. For cross-browser testing, the testing team makes use of real devices (hardware) and browsers.

### Assess the Integration of Third Party Services 
Third-party integrations have elevated user experiences. They help to extend a specific app’s or website’s functionality. However, all third-party integrations are not developed by trusted organizations. Many individual developers also release their integrations publicly, which may sometimes be faulty. 
If users leverage faulty integrations with an app or website, it ultimately degrades the user experience. Hence, assessing the app for all third-party integrations is a must.

## Types of Front End Testing
 
Here are some different types of front-end testing:

### Unit Testing
Unit testing evaluates an application’s or website’s components (smallest units) individually to verify that they function as intended. It is the lowest level of testing, where testers or developers take each component or feature and test it to ensure that it behaves as you want it to in production. This helps uncover defects in the early stages of development, leading to a reliable and stable codebase. 

### Integration Testing 
Integration testing checks whether the integration of unit-tested modules does not result in any errors and whether they communicate properly. It uncovers any bugs or errors resulting from the integration of unit-tested modules. Test stubs and test drivers are used to carry out integration testing. 

### Acceptance Testing
 
As the name suggests, acceptance testing evaluates the application or website for its acceptability. It is categorized into two types – User acceptance testing (UAT) and Business acceptance testing. The former evaluates the app to verify that it meets the specified end-user requirements. The latter assesses the app to check whether it complies with business objectives and technical requirements. 

### Visual Regression Testing 
It is apparent that every development team makes frequent changes to the code. Regression testing ensures that any recent changes made to an application or website do not affect its existing functionality. Hence, it is an inevitable software testing type for every test suite. 

The same logic applies to [visual regression testing](https://testgrid.io/blog/visual-regression-testing-guide/). However, the difference here is that regression testing is performed to check the effect of code changes on visual elements. It involves capturing the screenshots of the UI before and after making code changes and comparing them to determine any differences using image comparison tools. 

### Accessibility Testing
 
Accessibility testing is the subset of usability testing. It ensures that your app or website is accessible to every kind of user on the internet, including people with disabilities (hearing and visual impairment) or other special requirements. It verifies that any individual can access the app’s features under any condition. 

### Performance Testing
 
An app’s or website’s performance plays a vital role in improving user experience. Some major app performance metrics include responsiveness, scalability, end-user experience, stability, and reliability. 
Performance testing ensures the app or website is highly responsive, stable, and scalable under specific conditions. The app or website is put through varied loads to determine its performance and uncover potential bottlenecks that may degrade the user experience. 

### Cross-Browser Testing
 
As the name indicates, cross-browser testing verifies that a website works well across distinct browser and device combinations. It involves executing the same set of test cases across different combinations of devices and browsers and their versions. By doing this, you can ensure that your website is compatible with each browser and its versions. 

## Challenges of Front End Testing
 
Let us now throw light on some of the most common challenges of front end testing:

### 1. Constantly Evolving UI 
The app’s core library and third-party components are upgraded every few months, and upgrading any library requires you to change all other necessary components. As a result, every upgrade requires all components to be retested. This is one of the major challenges for the front end testing team. 

### 2. Determining Crucial UI Elements
 
The user interface of any application or website has multiple visual elements. These elements include graphics, formatting, layout, visible text, and functional aspects, such as buttons, submit forms, clickable links, etc. 
Front end testing checks how fast these elements load, how responsive they are, and how quick they are at executing user requests. 
As there are a lot of elements and aspects to evaluate, it becomes challenging for the front end testing team to prioritize testing the most crucial elements. To start with, check whether the pages load quickly with all the intended elements in the right place. Later, ensure that all functional elements respond to user requests. Finally, verify that formatting and all graphics load correctly. 

### 3. Simulating the Real-World Environment
 
Another major challenge in front end testing is simulating the real-world environment to test applications or websites. Usually, any app or website is tested in a controlled environment. Hence, it becomes difficult to get an idea of how it works in the real world, i.e., outside of the controlled testing environment. 

### 4. Choosing the Right Automation Tool
 
As front end testing involves evaluating a lot of elements, and that too after every update, it is not feasible for manual testers to accomplish it. This is where the role of automation tools comes into play. 
Well, there is a plethora of automation testing tools available for front end testing. Hence, it becomes overwhelming to choose the right one. Also, it is important to note that you must choose the tools based on the type of testing you want to perform. For instance, if you want to carry out performance testing, a few tools to consider are Jmeter, LoadRunner, NeoLoad, and LoadUI. 

### 5. Detecting Cross-Browser or Cross-Device Issues
 
People across the world use different versions of browsers and devices to access the Internet. As a result, testers must cover a massive range to test the application or website to evaluate its readiness for real-world use. However, this is challenging as new versions of browsers and devices are released constantly. Hence, testers need to keep up with the new versions to perform testing. 

## Front End Testing Best Practices 
Here are some of the best practices to follow when testing your app’s graphical interface:

### 1. Use the Testing Pyramid
 
The testing pyramid serves as a framework that provides a sequence for the types of tests to be performed on an application or website. In short, it serves as a blueprint for novice testers. 
Unit testing is present at the bottom of the testing pyramid, with integration testing at its top. The topmost tier is end-to-end testing. After these tests are done, add visual regression testing, acceptance testing, performance testing, etc., to the testing pipeline. 

### 2. Prioritize Front End Elements
 
The front end consists of hundreds and sometimes thousands of UI and functional elements. UI elements include formatting, text, CSS, and graphics, while functional elements include forms, links, buttons, etc. 
It is important to decide the testing priority of these elements. For instance, testing text, images, load time, and other essential features are priority elements, followed by graphics and layout. 

### 3. Use Real Browsers and Devices
 
Using real browsers and devices while testing provides an idea of how the app or website will actually function in the real world. It is better to avoid using simulators and emulators. 

## Conclusion
 
Front end testing is an indispensable aspect in the development of any software application or website. It verifies that the app’s or website’s presentation layer is free from bugs and has all the intended elements appropriately placed and functioning correctly. It ensures that the app or website provides the best user experience possible. 
Besides, front-end testing requires meticulous planning and execution. In addition, the success of testing depends on the right tool.
Source : This blog is originally published at [TestGrid](https://testgrid.io/blog/front-end-testing/)