Overview of Functional and Non Functional Testing with Example

What is Functional Testing?

Functional Testing is the part of Automation testing. The primary goal of functional testing is to validate the functionalities or to check all functionalities are properly working not as per user requirements. Functional testing is done as per the user concern and trying to make it as user want. Functional Testing involved black box testing.

In the functional testing tester first test each component’s functionality, not the structure to confirm desired output. Functional testing continues throughout the development cycle and into production. Functional testing is very important in Software Testing.

How to do functional testing?

As per the client or design has team given requirements functional testing is executed using the functional specification.

To perform functional testing you must do the following steps –

1. Understand the client requirements.
2. Identify test input data.
3. Determine the expected result.
4. Execute the test cases.
5. Compare actual and expected results.

Functional Testing Types with Examples:

There are different types of functional testing techniques which is are used to achieve the quality of software. Below are some important types with example –

• Unit Testing :

Unit Testing is the smallest part of the application in which individual modules are tested to determine if there are any issue occur by a developer.

For example – you are testing a function; then you have to check whether loop or statement in a program is working properly or not then this is called as unit testing.

• Smoke Testing:

Smoke testing is another types of functional testing in which developer test the basic functionality of the build. Smoke testing checks whether the software under test is ready for further testing.

Example: For Example in a project there are four modules like login, view user, user detail page, and new user creation, etc. So in this four modules first of all developer perform the smoke testing by executing all the major functionality of modules like a user is able to login or not with valid login credentials and after login new user can be created or not, and a user that is created viewed or not. This is the called smoke testing always done by developing team before submitting the build to the testing team.

Once the build is released to the testing team then the testing team has to check whether to accept or reject the build by testing the major functionality of the build. So this is the smoke test done by testers.

• Sanity Testing:

Sanity testing is the process of testing the bugs fixed in the new build. Sanity testing performs after smoke testing is performed.  

For Example in a project, there are five modules like login page, home page, user detail page, new user creation, and task creation etc. So we have the bug in login page like on login page password field accepts the less than five alpha-numeric characters which are against the requirements as in requirements it is specified that password should not be below than five characters but as password accepts the less than five characters it is the bug.

So now the bug is reported by the testing team to the developer team to fix it. When the developing team fixes the bug and passed it to the testing team than the testing team checks the other modules of the application means checks that fix a bug does not affect the functionality of the other modules, do not go deep to test the details because of the short time so this is the sanity testing.  

• Integration Testing:

When two different individual module integrated, integration testing performs to check after integration functionalities, performance etc are working properly or not.

• Acceptance Testing:

The primary goal of acceptance testing is to test whether software system has met the requirements or not. Acceptance testing is done by the user or by the client.

• Regression Testing:

Regression testing is the types of software testing which is used to check that new code changes should not have side effects on the existing functionalities.

What is Non Functional Testing?

Non functional testing focus on the quality of the software system. So tries to deduce how well the system performs as per the customer requirements means nonfunctional testing helps verify that customer expectations are being met or not.

Non functional testing is concerned with non functional requirements and is designed specifically to evaluate the readiness of a system according to the various criteria which are not covered by functional testing.

Types of Non Functional Testing

1. 1. Performance Testing: Performance testing measures the performance of system also it determine how fast some aspect of the system perform in term responsiveness and stability under a particular workload.
2. Load Testing: Load testing determines a system response time under both normal and peak conditions. It helps to identify the maximum operating capacity of an application.
3. Volume Testing: Volume testing refers to the testing a software application with a certain amount of data.
4. Security Testing: Security testing is basically to check whether the application is secure or not.
5. Compatibility Testing: Compatibility testing is basically the testing of the application or the product built with the computing environment. It test whether the product built is compatible with the operating system, hardware or other system software or not.
6. Usability Testing: In simple word, Usability is the process to test how your application is easy to use. It tests that whether the application or product built is user-friendly or not.
7. Scalability Testing: Scalability testing is used to measure its capability to scale up or scale down in terms of any of its non functional capability like the no. of transactions, data volume etc.

Stress Testing: It is a form of testing that is used to determine the stability of a given system. The goal of such type of testing to ensure the software does not crash in conditions of insufficient computational resources.

Difference Between Functional Testing and Non Functional Testing:

Functional Testing	Non- Functional Testing
1. In functional Testing, tester tests how well the system performs.	1. In Non-Functional Testing, tester tests how well the system responds.
2. Functional Testing is based on client requirements.	2. Non- Functional Testing is based on client expectations.
3. Functional Testing means Testing the application as per the business requirements.	3. Non- Functional Testing means Testing the application against clients and performance requirements.
4. It is a part of System Testing.	4. It is also a part of System Testing
5. Functional Testing Validating the behavior of an application.	5. Non- Functional Testing Validating the performance of an application.
6. This Testing covers Unit Testing, Integration Testing, Smoke Testing, Sanity Testing, Regression Testing and so on.	6. Non- Functional Testing supports Load/Performance Testing, Stress/Volume Testing, Security Testing, Installation Testing and so on.
7. It always concentrates on customer requirements.	7. It always concentrates on customer expectations.
8. Functional Testing means how is your system is doing.	8. Non- Functional Testing means how well your system is doing example usability, performance, and stress testing.

Functional Testing vs Unit Testing vs Integration Testing:

1. Unit testing is performed to check the smallest units or smallest executable part of the code of the product at a time. Integration testing is use to check whether different pieces of module working in a proper way. Functional testing is used to check certain functionality of the product or to check the whole system behavior as per the defined requirements.
2. Unit testing is done by developer team. Integration testing is done QA/Tester while functional testing is done by dedicated QA/Testing team.
3. Unit testing is not complex as it includes the smallest code. Integration testing is slightly more complex than unit testing. But the integration testing is more complex as compared to unit testing and integration testing because in that the whole system is checked at once.
4. Unit testing support for white box technique. Functional testing, perform black box technique. And for integration testing, they used both black and white box techniques also the grey box testing.
5. Unit testing finds the issues occurred in modules. Integration testing finds errors during or after the integrating different module. Functional testing finds an issue which is not allow an application to perform its functions, the scenario-based errors.
6. In Unit testing no chance of issue escape. While in integration testing less chance of issue escape. And in functional testing high chances as the number of test scenarios may be infinite.

	Unit testing	Integration testing	Functional testing
Definition and purpose	Testing smallest units or modules individually.	Testing integration of two or more units/modules combined together for performing tasks.	Testing the behavior of the application as per the requirement.
Complexity	Not at all complex as it includes smallest codes.	Slightly more complex than unit tests.	It is more complex as compared to unit and integration tests.
Testing techniques	White box testing technique.	White box and black box testing technique. Grey box testing	Black box testing technique.
Major attention	Individual modules or units.	Integration of modules or units.	Entire application functionality.
Error/Issues covered	Unit tests find issues that can occur frequently in modules.	Integration tests find issues that can occur while integrating different modules.	Functional tests find issues that do not allow an application to perform its functionality. This includes some scenario based issues too.
Issue escape	No chance of issue escape.	Less chance of issue escape.	More chances of issue escape as the list of tests to run is always infinite.

Non-Functional Testing Tips for Mobile App:

Mobile application development becomes the high demanding process. Most of the business mobile application so testing mobile apps are the most important and critical task.

You should check some condition for testing mobile app on any platform. Let’s see one by one.

• Analyze app business idea.

Firstly, you should understand the project specification and the app architecture. This will help you to find basic and small bugs that can easily fix by the development team.

• Functionality always goes first

Functionality testing is very important while building an app. For testing mobile app functionalities testing methodology cannot cover all conditions. For that, you have to collect all possible questions regarding the app. Create your own guide and test all the conditions to check the functionality.

• “Switch on” basic usability checks

App usability and functionality are two methods of testing. Before submitting an app first check the usability standards. This will help you to save your working time due to missing errors.

• Real environment testing is a must.

After testing all conditions, you should check your app in a real environment. Actually, any kind of mobile OS emulator will not show you the real problem with an app. Also using the various tools you can’t find the problem related to a specific region, device, or a mobile operator. The best solution for that checks the app on real devices and under real-life conditions by gathering your own global beta-team. For that, you just need to share a complete manual testing guide for the beta-testing process.

Functional Testing Tools

Today, there is number of paid and free software testing tools available in the market. And selecting a tool is very difficult, actually, it depends on your project requirements. You can use free tools also but there are some limitations in the features so it totally depends on you which on have to use.

Tools are divided into three parts:

• Test Management Tool
• Functional Testing Tool
• Load Testing Tool

Now we will discuss functional testing tools.

• Selenium

Selenium is today’s high demanding open source functional testing tool. You can download and use it for free of cost. It is used to test web application products and accepts multiple languages to its script such as PHP. C#, Java, Python etc. It is very easy to use and have many active users.

• Sahi

Sahi is an open source functional automation testing tool which provides support for testing web applications. Sahi is easy to understand and its the main concept is to support record and playback any web application, on any operating system. Sahi provides limited functionality as compared to other tools. Sahi support javascript-based script for programming.

• Unified Functional Testing (UFT)

Unified Functional Testing (UFT) is a commercial automation testing tool for functional testing. It is introduced by HP (Hewlett Packard). It provides multiple features such as web services, GUI testing, mobile application cross-platform testing. UTF support basic visual basic scripting to automate the script.

• TestComplete

TestComplete is a commercial testing tool used for web, mobile, and desktop application testing. It supports multiple languages such as VBScript, JavaScript, C++, C#. It has object recognition capability that can automatically detect and update UI objects.

• SoapUI

SoapUI used to perform functional testing and it’s supported for Eclipse, Netbeans etc. Using SoapUI testing you can improve the quality of services and application. SoapUI is easy to use and you can write test cases in a simple and easy way with SoapUI. On SoapUI you can run multiple environments just by changing the test setup.