What is Functional Testing?
Functional Testing is defined as a type of testing which 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.
Each and 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
What do you test in Functional Testing?
The prime objective of Functional testing is checking the functionalities of the software system. It mainly concentrates on -
- Mainline functions: Testing the main functions of an application
- Basic Usability: It involves basic usability testing of the system. It checks whether a user can freely navigate through the screens without any difficulties.
- Accessibility: Checks the accessibility of the system for the user
- Error Conditions: Usage of testing techniques to check for error conditions. It checks whether suitable error messages are displayed.
How to perform Functional Testing: Complete Process
In order to functionally test an application, the following steps must be observed.
- Understand the Software Engineering Requirements
- Identify test input (test data)
- Compute the expected outcomes with the selected test input values
- Execute test cases
- Comparison of actual and computed expected result
Functional Vs Non-Functional Testing:
|Functional Testing||Non-Functional Testing|
|Functional testing is performed using the functional specification provided by the client and verifies the system against the functional requirements.||Non-Functional testing checks the Performance, reliability, scalability and other non-functional aspects of the software system.|
|Functional testing is executed first||Non functional testing should be performed after functional testing|
|Manual Testing or automation tools can be used for functional testing||Using tools will be effective for this testing|
|Business requirements are the inputs to functional testing||Performance parameters like speed, scalability are inputs to non-functional testing.|
|Functional testing describes what the product does||Nonfunctional testing describes how good the product works|
|Easy to do Manual Testing||Tough to do Manual Testing|
|Examples of Functional testing are||Examples of Non-functional testing are
Functional Testing Tools
- Selenium - Popular Open Source Functional Testing Tool
- QTP - Very user-friendly Functional Test tool by HP
- JUnit- Used mainly for Java applications and this can be used in Unit and System Testing
- soapUI - This is an open source functional testing tool, mainly used for Web service testing. It supports multiple protocols such as HTTP, SOAP, and JDBC.
- Watir - This is a functional testing tool for web applications. It supports tests executed at the web browser and uses a ruby scripting language
In Software Testing, Functional testing is a process of testing functionalities of the system and ensures that the system is working as per the functionalities specified in the business document. The goal of this testing is to check whether the system is functionally perfect!!!