Functional testing

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. The advantage of performing an initial sanity test is that of speedily evaluating basic function.

In computer programming and software testing, smoke testing (also confidence testing, sanity testing,^[6] build verification test (BVT)^[7][8][9] and build acceptance test) is preliminary testing or sanity testing to reveal simple failures severe enough to, for example, reject a prospective software release. Smoke tests are a subset of test cases that cover the most important functionality of a component or system, used to aid assessment of whether main functions of the software appear to work correctly.^[6][7] When used to determine if a computer program should be subjected to further, more fine-grained testing, a smoke test may be called a pretest^[10] or an intake test.^[6] Alternatively, it is a set of tests run on each new build of a product to verify that the build is testable before the build is released into the hands of the test team.^[11] In the DevOps paradigm, use of a build verification test step is one hallmark of the continuous integration maturity stage.^[12]

Regression testing (rarely, non-regression testing^[13]) is re-running functional and non-functional tests to ensure that previously developed and tested software still performs as expected after a change.^[14] If not, that would be called a regression.

Usability testing is a technique used in user-centered interaction design to evaluate a product by testing it on users. This can be seen as an irreplaceable usability practice, since it gives direct input on how real users use the system.^[15] It is more concerned with the design intuitiveness of the product and tested with users who have no prior exposure to it. Such testing is paramount to the success of an end product as a fully functioning application that creates confusion amongst its users will not last for long.^[16] This is in contrast with usability inspection methods where experts use different methods to evaluate a user interface without involving users.