Functional testing

In software development, functional testing is a form of software testing that verifies whether a system meets its functional requirements. Generally, functional testing is black-box, meaning the internal program structure is ignored (unlike for white-box testing). Sometimes, functional testing is a quality assurance (QA) process. As a form of system testing, functional testing tests slices of functionality of the whole system. Despite similar naming, functional testing is not testing the code of a single function. The concept of incorporating testing earlier in the delivery cycle is not restricted to functional testing. Functional testing includes but is not limited to: A sanity check or sanity test is a basic test to quickly evaluate whether a claim or the result of a calculation can possibly be true. It is a simple check to see if the produced material is rational (that the material's creator was thinking rationally, applying sanity). The point of a sanity test is to rule out certain classes of obviously false results, not to catch every possible error. A rule-of-thumb or back-of-the-envelope calculation may be checked to perform the test.