Functional Testing vs Non Functional Testing

May 23, 2019

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Software testing is an immensely important process that helps both developers and testers in determining the quality, functionality, performance, and other important features of the software. Divided mainly into two testing categories, functional testing and non-functional testing, it tests not only the basic requirements of the software, but also ensures it compatibility, reliability, scalability, security, etc. To understand the process of testing in general, it is vital for us to know all about functional & non-functional testing. Therefore, here are points of differences between functional testing vs non-functional testing for your reference.

What is Functional Testing?

A quality assurance (QA) process,functional testing is a type of black-box testing, which involves complete integration of the software system to evaluate its compliance with the specified requirements of the client. Functional testing evaluates the performance of individual functions of a software application and ensures that its various components & features work as intended in the real world and meet the requirements & specifications of the client & their business. Hence, the test cases prepared for functional testing are based on the specification of the software component under test, which test application against client’s business requirements.

Performed either manually or with the assistance of automated tools, during the process of functional testing, testers test how well the system performs as well as its core functions, text input, installation, setup, usability, and more. Functional testing is an immensely valuable testing technique for validating that the output of the application is in compliance with the client’s requirements.

Areas Tested Under Functional Testing:

As it is stated above, during the process of functional testing various factors that determine the functionality and performance of the application are tested. These can be categorized into four types, which are mentioned below:

• Functions: Testers test the core functions of the software application.
• Usability: Here the basic usability of the system is tested, wherein the testers checks and verifies whether or not the users are able to navigate through the application effortlessly.
• Accessibility: Functional testing tests the accessibility of the application for users.
• Error Conditions: This is tested to validate whether the suitable error message are displayed or not when there is an error or issue in the system.

Important Features of Functional Testing:

• Evaluates the functional requirements & functionality of the software.
• The functional requirements are identified, specified, and decided prior to the development process.
• The chief purpose of this testing is to ensure the fulfilment of the functional requirement in the software product.
• It is based on business or client’s requirements.
• Validates the software behaviour.
• Responsible for accurate, desired, and proper working of each functionality of the software.
• This type of testing is the first priority of the tester.
• Manual testing is considered best for functional testing.
• It is a time consuming process.
• It encompasses following testing techniques:
• White box Testing.
• Black box Testing.
• Unit Testing.
• Integration Testing.
• Smoke Testing.
• Usability Testing.
• System Testing.
• Regression Testing.
• Globalization Testing.
• User acceptance Testing.
• Localization Testing.
• Interface Testing.

Functional vs Non Functional Testing Infographics

What is Non-Functional Testing:

A contrast of functional testing, non-functional testing is mainly concerned with testing the software application on the basis of non-functional requirements, such as usability, performance, reliability, scalability, etc. The objective of this testing is to test the readiness of the application as per the non-functional requirement, which are overlooked during the process of functional testing. Moreover, it evaluates the competency & effectiveness of the application under various load and conditions. During this type of software testing, the prime focus of the tester’s is on validating impeccable user experience.

With the assistance of non-functional testing, software engineers are able to optimize the way product is installed, setup, executed, managed, and monitored. Non-functional testing is as important as functional testing as it helps reduce the production risk and cost, which are associated with the non-functional aspects of the product. Additionally, non-functional testing plays a major role in ensuring that the quality attributes of the software product are identified correctly.

Areas Tested Under Non-Functional Testing:

While performing non-functional testing, software testers are focused on testing application against the non-functional requirements. Here, the prime objective of testing is to ensure optimum user experience. Therefore, some of the parameters tested by non-functional testing are:

• Security: This type of testing prevents the software system from sudden & deliberate attacks from internal & external sources.
• Reliability: Ensures that the software product performs continuously without any failure.
• Flexibility: This helps testers validate that the software can easily work on various hardware & software configurations.
• Interoperability: Checks software system’s interoperability with other software systems.
• Efficiency: Determines the limit of the software system’s capacity, quantity, & response time.

Important Features of Non-Functional Testing:

Examines the non-functional traits & aspects of the software.

This testing is based on client’s expectations and non-functional requirements.

The objective of this type of testing is to evaluate the software’s ability to meet the unforeseen requirements, needs and expectations of the customer in unwanted circumstances.

It is dependent on end user’s expectations.

Non-functional testing is mainly concerned with the performance of the software product.

It usually performed after the execution of functional testing.

Automated testing is an effective approach for the execution of non-functional test cases.

The process of non-functional testing is not time consuming.

It is also a part of system testing.

The various testing performed under non-functional testing are:

• Availability Testing.
• Compatibility Testing.
• Load Testing.
• Endurance Testing.
• Localization & Internationalization Testing.
• Performance Testing.
• Maintainability Testing.
• Recovery Testing.
• Configuration Testing.
• Compliance Testing.
• Installation Testing.
• Documentation Testing.
• Security Testing.
• Reliability Testing.
• Volume Testing.
• Scalability Testing.
• Usability Testing.
• Stress Testing.

Conclusion:

Though immensely different from each other, functional testing and non-functional testing, both are vital part of Software Testing Life Cycle (STLC) as they assist testers various important features and components of the software product, such as its quality, functionality, performance, and more. Hence, performing functional testing and non-functional testing is extremely important for testers to ensure that customers get remarkable user experience, with innovative and unique features.