Difference Between Functional and Non-Functional Testing

26Mar, 2024

The quality assurance strategies involve both non-functional & functional testing methodologies. Understanding the classification of functional & non-functional testing is necessary before carrying out the testing process. Software testing or functional and non-functional testing in software testing is necessary to evaluate whether the software/application meets the expected requirements.

It is necessary to verify the product is free of any malfunctions before releasing it. The aim of performing software testing is to address the errors and resolve them. When your software development project is being developed, you should consult with manual testing experts to understand the testing procedure.

In the following blog on functional and non-functional testing, we have mentioned a brief about functional & non-functional testing and best practices.

What is Functional Testing?

Want to know what is functional and non-functional testing? So, Functional testing validates that all of the software/app functions work by the requirements. Black box testing is one of the techniques used in this testing. By supplying the proper input, confirming the results, and contrasting the real & predicted outcomes, every aspect of the system is evaluated. Throughout the testing, the application security, UI, app functionality, database, etc., is checked. The testing can be processed by manual and automated methods.

Key Characteristics of Functional Testing

  • Verifies Software Actions

Through functional testing, businesses can verify the software actions and ensure all the actions are up to the mark and match user expectations.

  • Based on User Requirements

Functional testing is the way to match the software/app function to the user’s requirements. It validates the app matches the UI, app functionality & database.

Read Also: Salesforce Test Automation: From Challenge to Solution in Steps

Common types of functional testing

1. Unit Testing

The practice of testing specific parts of software to make sure that different aspects work as expected before evaluating the whole software package is known as unit testing. Unit testing verifies all inputs produce the single intended output, hence validating a component’s function. Unit testing accelerates development and delivers more effective code when carried out correctly. Developers typically use codeless automated tools for unit testing.

2. Integration Testing

Software module compliance is confirmed by integration testing. Integration tests ensure that each application component complies with its legal obligations and raise concerns when these interactions result in regressions.

3. System Testing

System testing is performed to ensure that it functions as an integrated unit. System testing is typically carried out by a quality assurance team before the functional testing of individual modules and the integration testing of every element.

4. User Acceptance Testing (UAT)

This kind of testing is carried out by the customer to validate that the system is consistent with the requirements. UAT is a form of black-box testing that involves multiple end users. Programmers provide end-users or agents with access to all or part of the program during the user acceptability stage of testing to simulate real-life interactions & capability. User acceptability testing is time-consuming and expensive, & that’s why most businesses are still avoiding this.

What is Non-Functional Testing?

Before you know the difference between functional testing and non-functional testing, understand what non-functional testing means. Non-functional testing is done to confirm that the program satisfies its non-functional criteria. It checks to verify if the system matches the requirements. It examines every aspect that functional testing does not examine. In the section below, we will share a brief on functional and non-functional testing types.

Key Characteristics of Non-Functional Testing

  • Focuses on Software Attributes

It verifies the behavior of the software. It ensures that the software attributes match the customer’s expectations.

  • Ensures Performance, Usability, and Reliability

Through non-functional testing, an organization can ensure their users that the application is working top-notch in terms of usability, reliability, and performance.


Most Common Types of Non-Functional Testing

1. Performance Testing

Testing for performance verifies that the software system performs quickly to requests. A user’s experience is destroyed by poor delay, and concise performance tests often identify issues before users do.

2. Usability Testing

This testing is necessary to verify the quality of the app to fulfill the user experience. Usability testing is a manual testing process. It is worth integrating this type of testing into the SDLC process. The unintuitive interfaces of applications or confusing dashboards of any software can hamper the quality of software applications. Through usability testing, you can accelerate the user experience.

3. Security Testing

Security testing services should be done regularly if you don’t want to hamper your business integrity. Depending on how vulnerable an application is to attacks, security testing can take many different forms, including automatic scanning and recurring penetration testing. Security testing validates the application has zero flaws & vulnerabilities. This is how you can bring more users to access your application without having any fear of losing data. This testing aims to focus on the access control, authorization & authentication of applications.

4. Compatibility Testing

Compatibility testing is another kind of non-functional testing approach. It verifies the application’s compatibility with various environments. Through compatibility testing, businesses can check how well their application/software functions in terms of reliability, usability & performance. The testing is further classified into two types of testing, which are forward testing & backward testing. By carrying out these procedures, you can evaluate the potential issues before deployment and accelerate the security & user experiences.
Through the above discussion, it is clear what the difference between functional and non-functional testing is.

Key Differences Between Functional and Non-Functional Testing

  • Purpose and Focus

Functional testing evaluates the functioning of the program to a list of standards or criteria. Non-functional testing evaluates an application’s characteristics, like speed and reliability under load, which are not essential to performance but still enhance the overall user experience.

In functional and non-functional testing examples, the use case is utilized for documentation & understanding the situation. At the same time, non-functional testing is allowed to be recorded & understood as quality. Through functional testing, businesses can verify the function of the system, whereas non-functional testing allows them to understand the performance of the system.

Functional testing is necessary to specify the system feature, whereas, through non-functional testing, it is necessary to describe how software should function. The functional requirements verify that the application will meet user needs and that the non-functional requirements satisfy the customer’s expectations.

  • Test Basis and Criteria

A functionality test scenario is a collection of guidelines that specify how to test a certain software application function. It describes the procedures to be followed, the anticipated results, and the requirements that need to be met before the test may be conducted.
It is essential to provide input conditions, anticipated results, and the actions to run the test while developing functional test cases. QA Testers, programmers, and other parties can better comprehend the testing procedure and findings with the aid of clear documentation.
Functional test cases assist in offering trustworthy and flawless software to end users by methodically addressing a variety of features. They also support the overall excellence of the assurance process. Accurate non-functional tests are required. You are not able to acquire insight through it otherwise.

  • Testing Methods and Tools

There is an array of testing performed for mobile & web apps. For this reason, it’s critical to employ the right tools and techniques to achieve useful outcomes. The advanced devices provide ample space to test various components with ease. Before initiating testing, it is necessary to check whether the tools that need to be integrated are appropriate. Testing both components is essential for improving software performance.

Software applications are tested for function using functional testing techniques based on established criteria. The tools check if the program can be used as intended, is of high quality, and is easy to use. Choosing an effective testing tool is essential for software testing since choosing the wrong tool can result in extra costs, modification, and delay. It’s critical to establish criteria for the evaluation and choose the appropriate instrument to prevent this. Based on the programming language and systems, the appropriate tool might vary.

Read Also: A Comprehensive Guide to Software Testing Methodologies

Complementary Nature of Functional and Non-Functional Testing

Following the above points, you can briefly understand the difference between Functional and Non Functional Testing.

In the SDLC process, the efficiency of testing procedures is critical to guaranteeing the product’s reliability and dependability. Functional & non-functional testing, two key elements of software testing, are vital to this procedure. Every kind of testing has a particular function and helps the software development process succeed overall. Because of their distinctive actions, both functional & non-functional testing has become quite popular among testers.

Non-functional testing ensures durability, productivity, and dependability, whereas functional testing makes sure the program satisfies the functional requirements. Together, these methods of testing provide a complete assessment of the overall efficiency of the product. Increased competitiveness in the marketplace, reduced operating expenses, and improved client retention can all result from a well-executed functional & non-functional testing strategy.

Organizations may ensure that the software satisfies the intended functional & non-functional needs by integrating both types of testing. These tests are necessary to find possible delays, faults, or limitations in the program. The requirement evaluation, testing plans, execution of tests, results analysis, reports, & verification are the primary phases in the testing process. These stages offer a general structure to execute testing efficiently.

By considering the overall points now, you can’t say that functional testing is more important than non-functional testing. You can accomplish accurate and efficient testing coverage by comprehending the connections between different testing methods, appropriately structuring and planning your testing activity, setting objectives for testing, and exchanging tools and procedures.

A thorough quality assessment, improved client experience, mitigation of risk, speed, and flexibility. Integrating ideal testing strategies helps to meet regulatory/safety assurance and improve client retention and brand integrity. To guarantee that software is of outstanding quality, it is necessary to understand the complete difference between functional and non-functional testing.

Hope the above discussion helps you to understand, what is the difference between functional and non-functional testing.


How To Choose the Right Testing for Your Project?

  • Define the Testing Goals

Clearly defining your testing goals is vital before you start the selection. Think about the precise goals you are targeting with testing, including boosting customer satisfaction, guaranteeing regulation, or verifying the efficiency of the software. Setting precise goals will make it easier for you to work with a QA testing team since they specialize in the necessary fields.

Before choosing ideal testing, it is necessary to think about your project requirements, such as the project type, types of functional and non-functional testing, and size. The device or tool you select for testing should meet the project requirements. When you consult with the QA team, you should ask them a few questions about what languages they are going to use, which frameworks they will utilize, etc. If you are going to release a web app, then mention the supported browsers where you want to make your website accessible. Similarly, for mobile apps, you should list the operating system where you want to keep your application compatible with the users.

  • Understand the Budget Criteria

It’s critical to clearly define the software testing timeline and costs. Establish achievable goals for the amount of time needed to finish the testing process & decide the amount you would like to spend on testing. With the use of these details, you will be able to pick the right testing service providers. Before the team shares an estimated price, they keep their eyes on specific factors like time spent on the project, cost of tools that are going to be used, etc. Pick options that are available in fixed pricing plans.

  • Consider Privacy & Security

Software testing frequently entails gaining access to private information. Give preference to companies that have strong data safeguarding and safety protocols. Make sure they follow any data protection laws, such as HIPAA or GDPR, according to your sector. To protect your valuables, find out more about their data encoding, safety policies, & confidentiality agreements.

  • Flexibility & Scalability of the Project

Take the testing service supplier’s adaptability and capacity to grow into consideration. Check to see whether they can adapt to your evolving testing requirements as the project develops. Assess their capacity to manage high volumes, further testing needs, and unforeseen adjustments. A flexible QA testing associate will adjust to the changing requirements of your project without sacrificing the level of their work.

  • Consider the Expertise & Skill of the Team

When choosing a software testing solution, it is crucial to take your team’s background and skill set into account. Certain tools could call for extra education or experience, while others might be straightforward to pick up if your staff is already familiar with the fundamentals of the subject. Some companies train their employees to sharpen their knowledge of advanced testing tools. Before making any judgments, additionally, ensure that the chosen tool requires knowledge that your team already has.

  • Track the Testing Methodologies

It is essential to comprehend the testing procedures & resources of the testing company they use. Make sure they adhere to industry best practices, such as DevOps or Agile, to guarantee that they integrate smoothly with your development workflow. Find out what kinds of testing solutions the company provides, such as usability, performance, safety, and functional testing. Inspect the resources or tools they employ for reporting, monitoring errors, and test automation as well.

  • Consider the Quality Assurance

A trustworthy testing company should have established testing and standard assurance procedures that are well-specified. Find out how they handle bug tracking, testing case architecture, test execution, and test planning. Make sure the company follows all the industry standards compliance (e.g., ISO 9001) & certifications.

  • Focus on Communication Transparency

Seamless interaction is crucial for testing success. Evaluate the methods for interaction and responsiveness of the service provider. The testing provider should approach for open communication, frequent reports on progress, and easy access. Using this approach assures that the testing experts can collaborate seamlessly with another development team.

Various software assessment approaches carry out multiple testing levels. Selecting the appropriate testing technique is essential to guarantee that the result satisfies the customers’ satisfaction, durability, and functionality criteria.

Furthermore, whereas certain methods for testing need to be applied from the initial stages of developing software, some aim to evaluate the finished product to make sure it satisfies the standards of privacy and security. Knowing the different components of the testing approach will help you to organize before the time and stay within your allocated budget and timeline.

Boost Your Testing IQ: Functional vs Non-Functional Awaits!

The above blog contains the difference between functional and non-functional testing with examples. In conclusion, we can say that testing software is necessary during the SDLC process. When a business integrates advanced tools and methods for functional & non-functional testing, it ensures the delivery of the best software. If you want to level up your professional brand image by launching the ideal product, then integrate both functional & non-functional testing. Integrating these testing methodologies helps businesses to assure software quality. Hire manual software testing services to embrace your business identity and reputation.

Avatar for Mit Thakkar
About The Author
Digital Marketer at KiwiQA: Software Testing Service Provider Company Worldwide.

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