I’m all about finding deals, buying used, and then passing things along. However, used doesn’t always mean quality, and I’m a bit of a quality snob too. (I mean, I’m a QA Engineer…it comes with the territory).

So, what’s the first thing I do when I go to a thrift store, or buy something from a yard sale site, etc? I check if the item functions as it should – if it’s clothes for my kids, do they have holes or stains? Are they the right size? Color? If it’s an electronic toy, doe sit turn on and off? Do all the buttons/features work, etc? I functionally test before I buy, as I’m sure you do too without even realizing it!

Functional testing is a type of testing that does just what it says – it tests the function of something. So, for the Facebook login page, the function is logging in – so that is where your functional testing would be focused.

Functional testing is done by looking at the input and the output, so trying to log in and what happens when you do for different scenarios: invalid credentials (should give error), valid credentials (should log you in). This is where you verify all of the required functionality specified within Acceptance Criteria has been met.

Normally functional testing is done in a test environment such as dev or test, and it must pass functional testing before the code/feature can move on to other testing and environments.