Functional testing is a process of testing systems to ensure that the system is working as expected by the users and stakeholders. To conduct functional testing, it is important for the tester to understand when to go with functional testing and proven industry practices in conducting testing processes. Here, we discuss the process, types, significance and best industry practices for conducting functional testing.

Importance of Functional Testing 

In functional testing, testers check if all requirements listed in the software requirement specification (SRS) and business requirement specification (BRS) are achieved. Functional testing mainly pivoted at customer requirements are tested to see if the methodology checks that the application reflects the experience of the users and stakeholders.

The tester focuses more on the functional goals and program specifications of the software rather than the code. Functional testing is also called as black box testing. Functional testing is done to assure that products are ready to be released and tell us the status of products in real-time. Significantly it helps testers to uncover termination error.

Types of Functional Testing

QA team performs different types of functional testing during the entire software testing life cycle. Here are the functional testing types that QA team performs: 

• Unit Testing: The developer will perform Unit testing. Here, the developer primarily focuses on the internal logic of the code. Unit testing is a piece of code which tests the behavior of a function or class.
• Component Testing: Component Testing is performed once the Unit testing is done. Testing of individual modules/components without integrating all components to verify it results in the expected outcome or not.
• Regression Testing: Regression testing is a type of software testing that confirms code changes have not affected the existing features. While performing regression testing, the tester will execute both passed and failed test cases.
• Smoke Testing: Whenever the build is received for QA to test, the first thing is to do a smoke test on the build. Here, QA verifies whether the major functionalities of the application are working or not.
• Integration Testing: Integration testing is performed when all the individual modules or components are integrated. The reason for this level of testing is to find out faults hindering  the interaction or flow between all the integrated units or modules.
• Sanity Testing: Sanity testing is also called surface-level testing. The tester verifies that all menus, commands and functions available in the project are working fine. The main objective of this testing is to verify rationality of the system in order to proceed with more rigorous testing.
• System Testing: System testing will perform once the integration testing is done. In this type, testing of a complete and fully integrated software product is done. Here the tester tests from an end-to-end perspective.
• UAT Testing: User Acceptance Testing (UAT) is performed by the clients and end users. This testing happens prior to moving into the production environment. Here the goal of UAT is to check the end-to-end business flow.

Steps To follow in Functional Testing

• Identify features that the application is expected to perform.
• Create input data based on the function's specifications.
• Determine the outcome based on the function's specifications.
• Execute the test case.
• Compare the actual and expected outputs.

Functional Testing Process

• Understand functional specifications
• Define enter and exit criteria
• Test case designing
• Create input data and define Expected output
• Execute test cases
• While executing test cases, compare actual vs expected the output
• If actual result doesn’t match with the expected result, create a defect and sent the report to developer
• Perform regression testing
• Test sign-off

Benefits of Functional Testing

Functional testing plays an important role in evaluating performance of a software application before it’s delivered to stakeholders. 

• Scales up the quality of the product
• Make sure that all the customer requirements are met
• Produces defect-free application
• Reduces risks associated with this project
• Proves that the System is working fine

When Not to Use Functional Testing

Every coin has two sides, and so does functional testing. The application of functional testing has some boundaries, so the tester should be aware of when not to use functional testing. Here are those:

• Various logical mistakes in the software are not identified in the testing process.
• Focus is more on the results of the source code and not on how the developer implements the actual source code.

In functional testing, the tester should not only concentrate only on the functionality of the module, but should rather focus on structure too without ignoring functionality. This should profoundly be based on user’s perspective. 

About Author

Chandana works as a Software Test Engineer at V-Soft consulting. Her Software Testing career spans for more than 3 years. As a test engineer she gained sound testing knowledge in testing Web & Mobile Apps (Android & iOS) , GUI, Functional, Integration, System, Ad-hoc, Usability, Database, Smoke Regression and Retesting. Also, she is very proficient knowledge in Agile methodology and AI domains.