Functional testing is a type of software testing that checks the software system for compliance with functional requirements/specifications. The purpose of functional tests is to examine each function of a software application by providing appropriate input, checking the output against the functional requirements.
Professional web functional testing mainly involves black-box testing and does not touch the source code of the application. This testing checks the user interface, API, database, security, client/server communication, and other functionalities of the application under test.
Testing can be done in 2 ways: manually or automatically.
What do you test in functional testing?
The main purpose of functional testing is to check the functionality of the software system. It mainly concentrates on:
- Basic functions – testing the basic functions of the application
- Basic usability – involves basic usability testing of the system. It tests whether the user can move freely through screens without any difficulty.
- Accessibility – it tests whether the system is accessible to the user.
- Error conditions it uses testing methods to check for errors. It checks whether appropriate error messages are displayed.
How to perform functional testing: the full process
To functionally test an application, the following steps must be taken:
Functional and non-functional testing
| Functional testing | Non-functional testing |
| Functional testing is performed using the functional specification provided by the customer and tests the system against functional requirements. | Non-functional testing tests performance, reliability, scalability, and other non-functional aspects of the software system. |
| Functional testing is performed first | Non-functional testing should be performed after functional testing. |
| Business requirements are the input data for functional testing | Performance parameters such as speed, scalability is the input data for non-functional testing. |
| Functional testing describes what the product does | Non-functional testing describes how well the product performs |
| Easy to do manual testing | Hard to do manual testing |
| Examples of functional testing: | Examples of non-functional testing: |
| Unit testingSmoke testingCommon sense testingIntegration testingWhite-box testingBlack-box testingUser testingRegression testing | Performance TestingLoad testingVolume testingLoad testingSecurity testingInstallation testingPermeability testingInteroperability testingMigration testingFunctional testing tools |
As mentioned before, testing can be done in two ways: manually or automatically:
Advantages of manual testing.
- A tester’s report is the first feedback from the potential customer, which will allow you to understand how convenient the product is for the end-user.
- UI feedback.
- Using a professional manual testing services is the only way to test the application’s overall design and identify its flaws.
- Cost.
Advantages of automated testing.
- Automated testing allows you to significantly speed up the release of a software product and reduce the cost of test iteration. In today’s world, the speed of release of software products is an integral part of a competition.
There are several functional testing tools available on the market:
- Ranorex Studio is a feature-rich automated testing system for desktop, web, and mobile applications with a built-in Selenium WebDriver.
- Selenium – A popular open-source functional testing tool.
- QTP – an easy-to-use testing tool by HP.
- JUnit – used mostly for Java applications and can be used in the unit and system testing.
- soapUI is an open-source functional testing tool mainly used for web services testing. It supports several protocols such as HTTP, SOAP, and JDBC.
- Watir is a functional testing tool for web applications. It supports tests run in a web browser and uses the “ruby” scripting language.
Functional testing is the process of testing the functionality of a system and making sure that the system works according to the functionality specified in the business document. The purpose of this testing is to verify if the system is functionally perfect.