Functional Testing and basic steps to apply

Go to previous article – System Testing and it’s types

What exactly is functional testing?

In a nutshell, a functional testing is a quality assurance black-box testing process that is in charge of describing what a system does. It tests the software to make sure it meets the functionality requirements expected of it and that the output it is providing is the same output required by the end-user.

As this involves black-box testing, the source code of whatever application is being tested is not touched nor worried over. Every single function is tested in the same way and the process is self-explanatory: feed in the appropriate input, verify and examine the output, and compare the actual vs. expected results of the test.

Functional testing is quite flexible as it can be executed either Manual testing or Automation testing, whichever way is most convenient and desirable by the tester.

User interface, API, and security are a few of the processes checked thoroughly. Since functional testing mainly focuses on the functionality of the software system, mainline functions, basic usability (navigation), accessibility, as well as error conditions (proper display of error messages) are concentrated on.

There are six basic steps to functional testing:

  1. Understand requirements- Understand what is expected from the test and identify the functions that should be tested.
  2. Identify test data- Identify what data should be used as the input based on the specifications of the function.
  3. Evaluate outcome- Compute the outcomes expected with the input data that was selected.
  4. Begin testing- Execute the test.
  5. Compare- Compare the actual results vs the results that were expected to determine where the software performed correctly or incorrectly.
  6. Final check- Once the entire test has been completed, check to make sure the application works per the requested requirements


As seen in the six basic steps above, functional testing is quite efficient. There are a few different types of functional testing available. These include: smoke, sanity, integration, user acceptance testing, and regression testing.

You can run functional tests manually or using any functional automation test you wish.  Here are some of many tools available for a tester to be able to properly perform a functional test.

  • SoapUI- this is an open source tool used mainly in web testing. It supports HTTP, SOAP, and, JDBC.
  • Watir– this tool is used for web applications as well. Watir is used for functional testing done in web browsers and it uses a scripting language called Ruby.
  • And hundreds of additional tools you can check out on our tools sections.

Read more about other testing methods


Go to next article – Software testing methods – Agile Vs Waterfall

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3 Comments - Write a Comment

  1. Thanks Girls! I’m happy you found it useful!!!
    If you have any more questions you’re welcome to ask away and I’ll try and answer as soon as I can.
    Tali and STTools Team

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