What is testing?

Software testing is a pool of knowledge and endorsement which has always been a career option to many is now a point of discussion. It is a buzzword in the software industry until the 1980s. The term software tester generally refers to any tester. But in the recent growth of technology you can see it as a separate profession. Talking about the goals in software testing different organizations established tester roles such as a Test Manager, Test Lead, etc. Testing is basically a process to evaluate the functionality of any application and to find out that all the requirements are met.In order to run the process defect-free, the primary purpose of testing is to detect the software failures, so that it is easy to find the defects and correct it. Based on the user reuqirements testing has two major types – Functional testing versus Non-functional testing

Why testing is widely used? Different organizations use testing to improve the rate of production. It provides the objective some information about the quality of the software and the risk of its failures to the users.

Let’s compare the two types of testing.

Functional testing

Functional testing is a type of software testing where you test the system against all the functional requirements or specifications like the technical details, data manipulation, processing and other specific functionalities. You might think functional testing just refers to testing a function or a method of your module or any class, but that’s not what it does. Functional testing helps in testing a slice of functionality of the entire system. It is also a type of blackbox testing that holds the test cases based on the specifications of the component under test. Now you might ask what is blackbox testing.

Blackbox testing

Blackbox testing is a method of software testing which helps in examining the functionality of an application without puring into its internal structure or the implementation process. This basically means that the user will not know the internal process that takes place while testing a case, so this type of testing also checks whether the application works as per the customer need.

black box testing
black box testing

Non-functional testing

Non-functional testing is another type of software testing which is used to check the non-functional aspects of a system like the performance, the usability, readability and so on. It helps in testing the readiness of the system. Non functional testing defines the way a system operates rather than pointing out the specific behavior of the system. This is totally in contrast to the functional testing which tests against the functional requirements that describes the functions of a system. Basically you can do non-functional testing to check and evaluate the non-functional parameters. Non-functional testing is equally important as functional testing. All the non-functional parameters such as speed, scalability, security, reliability, efficiency of an application is tested under the non-functional testing.

Functional vs Non-functional

So now, that you’ve understood what is functional testing and what is non-functional testing let’s move on and understand the parameters, based on which we’ll compare these two types of testing. We’ll compare them based on these particular parameters starting from their objective. Firstly, we’ll discuss on how these two testing types differ based on their objective. Secondly, we’ll move on to their area of focus or where exactly you do testing.


Let’s start comparing them based on their objectives. Functional testing is carried out to verify or validate the software actions like the login functions. Whereas the non-functional testing helps in verifying or validating the performance of the software, that is how the system performs under a given situation or condition.

Area of focus

area of focus

Functional testing mainly concentrates on the user requirements. That is what are the functionalities that takes place in the process. Whereas the non-functional testing mainly concentrates on the user expectations. That is how the system:

  • interacts with the user
  • is built
  • how you can customize your functionalities


Functional testing finds it easy to execute the blackbox testing. It supports black-box kind of execution whereas the non-functional testing finds it easy to execute the white box test cases. White box testing is testing the internal structure or the implementation the user can actually see the process that takes place in the system. Functional testing helps in describing what the system should do whereas the non-functional testing describes how the system should work.

Functional testing helps in defining the test cases. This is the reason why the execution of the functional testing happens before the execution of the non-functional testing. In other words the non-functional testing execution takes place only after you define the test cases.

Types of Functional testing

Unit test

Testing comprises of the unit test. Unit test is basically the first phase of testing. You can prepare the test cases, review them, rework on them if there are any errors and create a baseline for the test cases. This particular type helps in testing the units of the test case.

Integration testing

Integration testing is the level of software testing where the individual units are combined and tested as a group.

System testing

If you want to test the entire system on a whole, how would you do that? We will use a system testing. System testing is actually a series of different tests whose sole purpose is to exercise the computer-based system. If you want to run the test strips on another system how would you do that? We will use interface testing.

Interface testing

Interface testing verifies whether the communication between two different software systems is correct.

Regression testing

Regression testing is the test to confirm that the recent program or code change has not adversely affected the existing features. You need to have a test scripts which doesn’t change even if there are modifications.

User acceptance testing

The last phase of functional testing is user acceptance testing. User acceptance testing helps in handling the real-world scenarios according to the specifications.

Don’t forget to check functional types of testing when testing websites at website testing strategies.

Types of Non-functional testing

Now let’s move on to understand the different types of non-functional testing. Start by understanding the first type, that is the documentation testing.

Documentation testing

Documentation testing helps in estimating the testing effort required, the test coverage and how to track the requirement. These are the particular features of documentation testing. Once you finish the documentation process and you want to install any particular software to your system, what if there is a bug in it, how would you test it? We are going to use a type of non-functional testing called installation testing.

Installation testing

Installation testing checks if the software application is successfully installed and it is working as expected. Now say if you want to check the performance of a system how would you do that?

Performance testing

Performance testing is basically considered as the heart of testing. Above all you can use it to ensure that the software application will perform well under any expected workload. Performance testing has many types.

Load testing

Load testing is used to monitor the response time and staying power of any application when the system is performing well under heavy load.

Stress testing

Stress testing is used to determine or validate the applications behavior when it is pushed beyond the normal or peak load conditions.

Endurance testing

Endurance testing involves testing a system with the expected amount of load over a long period of time to find the behavior of the system.

Reliability testing

Reliability testing checks whether the software can perform a failure free operation for a specific period of time. It also assures that the product is fault free and is reliable for its intended purpose. Now let’s try to understand the last phase of non-functional testing – that a security.

Security testing

Testing security helps in determining that its data and resources are protected from possible intruders. Testing security is the key to software testing.

Use case

So this is about the different types of functional and non-functional testing. Let’s understand the use case of functional testing. For instance, functional testing helps in checking the login functionalities. Say if you want to login to a particular webpage and you want to sign into an account you will have to fill a few details like your name, your mail, ID, create a new password and so on. These particular fields you check using functional testing.

Now let’s understand the use case of non-functional testing. Non-functional testing helps in customizing the test cases according to the user requirements. For example after logging into a webpage you want the particular page to lower for a few seconds and then pop up. You check this kind of customization using non-functional testing. More information on functional and non-functional testing you can check here.

This is about non-functional versus functional testing, if you want to learn more about website testing don’t forget to take a look at our blog.