What is Functional Testing? Types and Examples

As someone with extensive experience in software testing, I have had the opportunity to explore various facets of this critical phase in the software development lifecycle and I am excited to share my thoughts regarding the subject. It is one of the essential processes that ensure that software applications work appropriately. 

It helps validate the outcomes of each of the functions that the software is intended to use. It would help if you validated each of the functions of an application against all the requirements. 

Functional planning also helps to guarantee a product is not only functional but also reliable and user-friendly. 

What is Functional Testing?

Functional testing is the practice of understanding if the software applications are working appropriately. It involves testing the software to ensure that each function or feature of the software operates properly. This type of system involves understanding what a system does rather than the system involved in doing it. 

The primary goal of the software is to verify that it performs as it is expected when subjected to various conditions. Being a tester, I basically focus on the use of several user interfaces, APIs, databases, security, and even other related functionalities. 

Functional test planning mainly dives into the internal workings of the application rather than external behavior. It ensures that users can connect with the software in the way that they are supposed to. 

You can easily understand the importance of functional testing by looking at the fact that 24% of the companies have increased test automation within a year. 5% of the companies are also known to engage in complete functional testing 

Types of Functional Testing 

Several types of functional testing are available to target different aspects of a software’s functionality. Some of the common testing types include unit testing, integration testing, system testing, and acceptance testing. 

1. Unit Testing

This is the first level of unit testing, where the individual components of a software application are tested. The developers typically do this to ensure that each unit of software functions accurately. 

2. Integration Testing 

This system is known to include unit testing, and it focuses on interactions between integrated units of modules. This ensures that combined components of the application work together as per expectations. 

3. System Testing 

It is a comprehensive functional test plan that checks if the entire system is functioning appropriately. With this method, we ensure that the entire software with all its components is performing appropriately. 

4. Acceptance Testing 

This is the final stage, which is often conducted by the clients or the end-users. This test ensures that the software meets their expectations and requirements. Acceptance testing is the last phase before software is released for production. 

Read More: Software Testing Techniques

Benefits of Functional Testing 

Functional testing provides a lot of benefits of automation testing and it is indispensable in the software development lifecycle. Firstly, it aims to check if the system or software under consideration is working appropriately. 

The test includes understanding if the functionalities of a software are working appropriately and identifying any underlying defects. The process aims to resolve the defects earlier in the process, reducing costs and time associated with fixing these later. 

Secondly, functional testing aims to improve the quality of the software, ensuring it delivers the expected outcomes. Ultimately, the process seeks to help the software in meeting the user satisfaction pain points effectively. This reduces the risk of software failures and also eradicates the need to put in costly post-release patches in software. 

Lastly, functional testing is known to support the maintenance of the software, validating its new features. The system also aims to see if the existing functionalities are not adversely affected during changes. Moreover, I can affirm that continuous integration and continuous deployment practices help faster software releases. 

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Purpose of Functional Testing 

The primary purpose of functional test planning is to see if the software systems are performing correctly. When we are at the point of delivering the client's expected software, we ensure that it is perfect. Such testing ensures that we are helping in covering functional issues like incorrect calculations, data integrity problems, and user interface errors. 

Functional testing also serves the purpose of ensuring that the software is user-friendly and accessible. When we test the applications from a user perspective, we can identify any issues that might hinder user experience. Some of the issues that might cause problems in the UX (User experience) are:

1. Positioning of user interface

2. Unresponsive buttons

3. Broken links

The focus on usability is crucial in today’s competitive software market, where compatibility and satisfaction are important. Moreover, functional testing is also known to help in verifying the software’s compatibility with different environments. 

Some of the environments where I mainly insist beginners test their software are browsers, devices, and even different operating systems (OS). Therefore, it ensures that software is performing optimally across different platforms and providing necessary functionality. 

Best Practices for Functional Testing 

When you are trying to adhere to the best practices for functional testing, you will definitely will achieve effective results. I would suggest you thoroughly understand the requirements before starting the testing process. 

As a tester, I would advise you to have a clear understanding of what the software aims to achieve. Having a strong understanding of such processes provides you with a thorough understanding of designing effective test cases that cover everything. 

Another important thing that you must understand is that automating test cases is very important. While I would not suggest you automate all the functional test cases, automate the ones that can be done. You may try out automating regression tests, for a matter of fact, as it helps you save time during the development process. 

The next thing that you can try out is prioritizing the test cases. Based on the criticality of a function, it is highly appreciated that a series of priority tests be lined up. Critical functionalities that are essential must be tested first, and the less critical ones should follow it. 

Continuous testing and integration are other factors that directly align with the DevOps methodologies. By continuously testing the applications once a new feature is added, you can detect and resolve issues earlier. Ultimately, it ensures a smoother application development process for yourself. 

For latest Updates of Automation testing Read This: What is DataBase Testing?

Functional Testing vs Non-Functional Testing 

It would be best if you had a strong understanding of the non-functional and functional testing types of components. Functional testing is, as the name suggests, entirely dependent on testing the functionality of the software as per requirements. It is more concerned with what a system does and involves testing individual features or functionalities. 

However, in the case of a non-functional testing type, it evaluates how a system performs under several use conditions. It is not concerned with specific functionalities, but it depends on aspects of performance, scalability, usability, and security. Non-functional testing aims to check if or not the software can handle real-world scenarios or even challenges. 

Therefore, while functional testing checks the correctness of software, non-functional testing checks the software’s behavior and characteristics. Both of these characteristics are essential to delivering a high-quality software product. 

Functional Testing Examples

I am going to provide a few examples of functional testing. Suppose we take an example of testing an online shopping application. A functional test usually involves verifying that items are added to the cart, their prices, and, if available, the discounts are shown appropriately. 

We also dummy-track an order and see if the performance of the application in the back-end and front-end is accurate. Last but not least, we check if the payment methods are working fine to ensure users can pay for their orders quickly. 

Another application can be tracking a banking application, where the functional tests secure transactions. You can see if the transfers are safe using authentication processes that are present on-board when initiating a transaction. 

You can also take an example of a CMS (Content Management System), where functional testing becomes important. With the tests, I can verify whether the users can create, edit, or delete content. You can also check the management of permissions and set user roles of the system properly. 

Functional Testing Tools 

Several tools are available to facilitate functional testing. Some of them are:

• Selenium

• QTP

• TestComplete

These tools are known to help in the process of software development. While Selenium is used to automate web applications, QTP provides comprehensive testing solutions for both functional and regression testing. TestComplete is used to automate web, desktop, and mobile applications, etc. 

Also Read: Risk Management in Testing

Conclusion

Functional testing is a vital part of the software development process. It ensures that the software functions as intended, delivering the expected outcomes to users. Approving the capability of the application against the prerequisites helps distinguish and resolve issues.

By adhering to best practices for automation testing and using the right tools, you can conduct effective functional testing that adds value to the software development process. To learn more, consider joining an automation testing course today and make a difference!

Also Read: When to Use Automation Testing 

Frequently Asked Questions 

1. Who performs functional testing?

Developers and QA testers can both perform functional testing, and there are no barriers to it. Developers conduct unit and integration testing, while QA testers focus on User Acceptance Testing (UAT). However, in many cases (not rare), even the end-user or clients are also included in acceptance testing. 

2. Is QA testing functional testing?

Yes, QA testing often contains functional testing aspects as well. QA testers are responsible for letting the user know if the software is performing optimally. QA testing is a little bit different from functional testing in that it contains testing aspects like performance, security, and usability. 

3. Does functional testing require coding?

Functional testing does not always involve the requirement to code, especially for manual testing. Besides, some coding knowledge is often required for automated functional testing.

Test scripts are needed to be written in lines of code, which are supported by testing tools. You can also use tools like Selenium to automate tests using programming languages like Java or Python.