Functional Testing


Functional Testing

What is Functional Testing?

Functional testing is a form of testing and is a quality assurance process that provides validation on the system or components against various functional specifications and outlined requirements. Functional testing is a type of black box testing as the source code of the application is not considered during the testing process.

The main aim of this form of software testing is to test each functionality of the application by providing  inputs and validating the outputs against the functional requirements.

This form of testing verifies if the software performs in a way the users are expecting. This type of testing is completely based on program specifications, it is also known as specifications-based testing. In this testing process, QA engineers focus on validating the system against the functional specifications and verifies the features against specified set of user specifications.

Functional Testing is requirement?

The need for functional testing is vital in validating the quality and functionality of the software. Through this software testing, quality assurance teams verify the software functionality based on the Software Requirements Specification (SRS) and ensures the system functions as the user specifications.

This form of testing helps to check if the system is fixed for release and is error-free. This testing does not depend on any assumptions but it ensures to deliver high-quality product. Basically, this testing method is used to test usability features, specific error conditions, checks accessibility features along with testing other important functions of the software.

What are the different types of Functional Testing?

Unit Testing:

Unit testing is the first phase of the software development lifecycle.
This functional testing type is performed by developers and they write the scripts to validate to see if the small units of the application are working as the requirements or not.

Component Testing:

This functional testing type is similar with unit testing, but the critical difference is that it is performed by testers and it tests each object of the application separately with other software objects.

Smoke Testing:

Smoke testing is performed after each build is released. This functional testing type is also known as build verification testing. This process helps to test whether all the test environment aspects are running successfully and whether the build is stable or not and clarifies if the build can be used for further testing process.

Sanity Testing:

Sanity testing is usually performed after smoke testing, after receiving a software build with changes made. It is used to validate the code changes introduced continue to work as expected.

Integration Testing:

Integration Testing is one of the important software testing method where individual modules of the application are combined and tested as a group to identify the functionality after combining different modules.

Regression Testing:

This functional software testing method helps in ensuring the new changes made to the code  that are not affecting the already existing features or functionalities of the application.

System Testing:

This is also a functional testing method that is performed after integration testing. This system testing phase is used for validating the fully integrated software application.

User Acceptance Testing (UAT):

The final software testing phase, end-users or clients take up the roles of test engineers to validate the developed application if it is meeting the requirements or not. UAT is an important functional testing type that is performed before moving the application to production.

How to perform Functional Testing?


Best practices for taking up Functional Testing

Prioritize test cases and start writing earlier:

It is preferred to prioritize the test cases based on the complexity-levels and start writing test cases early in the requirements analysis and design phases to achieve better functional testing objectives.

Plan for writing reusable test cases:

Test cases needs a lot of time and skills to work on them. Thus, it is preferable to have reusable test cases to save time. To write reusable test cases, it is essential to write in simple language and ensure they are short and easy to execute.

 Test early and test often:

It’s essential to test early during the software development phase to know the bugs and issues and as features keep changing functional regression testing should be taken up to ensure existing functionalities remain unaffected with the new changes

Automate wherever possible:

Test automation is helpful to avoid repeated manual tasks and helps to automate processes to save time and cost. it is not possible to automate all test cases and it is essential for testers to decide which of the test cases should be automated.

5. Create a traceability matrix:

It’s essential to create a traceability matrix to capture all requirements given by the client and it maps the user requirements with the test cases. It’s helpful to ensure that all functionalities are covered while performing software testing.

What are the different Functional Testing techniques?

End-user based tests:

This functional testing technique, the system is tested to validate all the components to work perfectly in combination or not.

Equivalence tests:

This equivalence test technique, the test data is divided into various partitions and the data in each of the partitions has to respond in a similar way. Thus, tests are performed on one condition, if any one of the conditions fails in any partition, then the others stop working.

Boundary value tests:

This technique helps in validating how the system performs when boundary data limits are implemented. If the provided inputs are less than the boundary values, then the test is considered as negative testing.

Decision-based tests:

This decision-based test technique helps in verifying the possible outcomes that can be achieved when a status condition is satisfied.

Ad-hoc tests:

This testing technique helps in identifying the bugs that were not identified in any other tests. Ad-hoc testing works as a smart way to discover the bugs that are not identified before.

Some of the important Functional Testing tools                         

1.  Appium:

This is an open-source functional testing tool commonly used for performing functional testing for Android and iOS mobile apps. This tool supports multiple programming language such as Java, Python, Ruby, PHP, etc.

2.  AccelQ:

This is one of the popular automation tools designed for testing APIs. This tool allows an effective integration process between functional testing and API testing.

3. Tricentis TOSCA:

With this tool, it is easier to perform end-to-end functional testing. This tool helps to automate all the layers of modern enterprise architecture and helps in extending the already existing tests by allowing continuous testing within the CI/CD process.

4. Selenium:

Selenium is one of the popular open-source automation testing frameworks used testing web applications. Selenium tool supports a number of operating systems, environments and browsers. It provides a playback tool for authoring functional tests and runs on Windows, Linux, Mac, etc.

5.  TestComplete:

This is one of the widely preferred functional automation tools for desktop, mobile, and web applications. This tool supports number of languages such as C#, VBScript, C++. Is used to create automated tests across desktop, web, and mobile applications.

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