Function Testing is a type of quality assurance (QA) testing that consists of ensuring the compliance of a system or component against its specified functional requirements to ensure proper functionality. A black-box test cases on the specifications of the software component under test. This can be done during the development period, on a case-per-case basis for specific components developed by your team, or towards the end of a development project, when the various components of a project come together. The main idea is to look at the finished product and determine whether it does everything that it is supposed to do, and if it does so properly.
There are types of functional testing services such as: