Question

What is the differences between functional and non-functional testing?

Answer 1

Functional testing is mostly performed on the application to make sure that the functionality of the software is right. Like, black-box testing, unit testing, smoke testing. It is most likely a day to day task that needs you to test the functionality of an application as and when a new feature to the application is added.

Non-functional testing is mostly done before release to make sure that the software developed does not fail, it recovers in the case of failures. If it is an upgrade, it upgrades fine, if it has a large userbase, it should be able to serve them all. All these are an example of non-functional testing.

Functional Vs. Non-Functional Testing

Parameters	Functional	Non-functional testing
Execution	It is performed before non-functional testing.	It is performed after functional testing.
Focus area	It is based on the customer's requirements.	It focusses on customer's expectations.
Requirement	It is easy to define functional requirements.	It is difficult to define the requirements for non-functional testing.
Usage	It helps to validate the behavior of the application.	It helps to validate the performance of the application.
Objective	Carried out to validate software actions.	It is done to validate the performance of the software.
Requirements	Functional testing is carried out using the functional specification.	This kind of testing is carried out by performance specifications
Manual testing	Functional testing is easy to execute by manual testing.	It's very hard to perform non-functional testing manually.
Functionality	It describes what the product does.	It describes how the product works.
Example Test Case	Check login functionality.	The dashboard should load in 2 seconds.
Testing Types	Examples of Functional Testing Types Unit testing Smoke testing User Acceptance Integration Testing Regression testing Localization Globalization Interoperability	Examples of Non-functional Testing Types Performance Testing Volume Testing Scalability Usability Testing Load Testing Stress Testing Compliance Testing Portability Testing Disaster Recovery Testing

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Answer 2

While there is not much difference between functional and non-functional testing from a user point of view, if you look at it as a tester, then you might find many differences between them. Below is a detailed comparison of functional and non-functional testing:

Functional Testing	Non-Functional Testing
It is executed to analyze the functionality of components of an application as per the client’s requirements.	It is executed to check the performance, reliability, scalability, and other non-functional aspects of an application.
It is executed in the early stages of development.	It is generally performed after functional testing.
Can be performed both manually and with automation tools.	Requires automation tools for effective testing.
Focuses on user requirements.	Focuses on user expectations.
Determines what the product is capable of	Determines how effectively the product works
Business requirements are the inputs of functional testing.	Parameters like speed, scalability are the inputs of non-functional testing.
Examples of Functional Testing: Unit Testing, White Box Testing, Smoke Testing, Sanity Testing, Usability Testing, Regression Testing.	Examples of Non-Functional Testing: Performance Testing, Load Testing, Stress Testing, Security Testing, Installation Testing, Cross Browser Compatibility Testing.

Source: Automated Functional Testing

Answer 3

While there is not much difference between functional and non-functional testing from a user point of view, if you look at it as a tester, then you might find many differences between them. Below is a detailed comparison of functional and non-functional testing:

Read More: Functional Testing

Answer 4

Functional testing is a type of testing that verifies that each function of the software application operates in conformance with the requirement specification. This testing mainly involves black box testing, and it is not concerned about the source code of the application.

Every functionality of the system is tested by providing appropriate input, verifying the output and comparing the actual results with the expected results. This testing involves checking of User Interface, APIs, Database, security, client/ server applications and functionality of the Application Under Test. The testing can be done either manually or using automation

Non-functional testing is a type of testing to check non-functional aspects (performance, usability, reliability, etc.) of a software application. It is explicitly designed to test the readiness of a system as per nonfunctional parameters which are never addressed by functional testing.

A good example of a non-functional test would be to check how many people can simultaneously login into a software.

Examples of Functional Testing Types Unit testing Smoke testing User Acceptance Integration Testing Regression testing Localization Globalization Interoperability

Examples of Non-functional Testing Types Performance Testing Volume Testing Scalability Usability Testing Load Testing Stress Testing Compliance Testing Portability Testing Disaster Recover Testing

 

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