Smoke And Sanity Testing

Smoke testing
In computer programming and software testing, smoke testing is a preliminary to further testing, which should reveal simple failures severe enough to reject a prospective software release. In this case, the smoke is metaphorical.

Smoke testing is done by developers before the build is released to the testers, or by testers before accepting a build for further testing. Microsoft claims[1] that after code reviews, smoke testing is the most cost effective method for identifying and fixing defects in software.

n software engineering, a smoke test generally consists of a collection of tests that can be applied to a newly created or repaired computer program. Sometimes the tests are performed by the automated system that builds the final software. In this sense a smoke test is the process of validating code changes before the changes are checked into the larger product’s official source code collection or the main branch of source code.

In software testing, a smoke test is a collection of written tests that are performed on a system prior to being accepted for further testing. This is also known as a build verification test. This is a "shallow and wide" approach to the application. The tester "touches" all areas of the application without getting too deep, looking for answers to basic questions like, "Can I launch the test item at all?", "Does it open to a window?", "Do the buttons on the window do things?".

The purpose is to determine whether or not the application is so badly broken that testing functionality in a more detailed way is unnecessary. These written tests can either be performed manually or using an automated tool. When automated tools are used, the tests are often initiated by the same process that generates the build itself.

This is sometimes referred to as "rattle" testing - as in "if I shake it does it rattle?". Steve McConnell gives some good advice for smoke testing software.
http://www.stevemcconnell.com/ieeesoftware/bp04.htm

Sanity testing

In computer science, a sanity test is a very brief run-through of the functionality of a computer program, system, calculation, or other analysis, to assure that the system or methodology works as expected, often prior to a more exhaustive round of testing.

In software development, the sanity test (a form of software testing which offers "quick, broad, and shallow testing"[1]) determines whether it is reasonable to proceed with further testing.
Software sanity tests are commonly conflated with smoke tests.A smoke test determines whether it is possible to continue testing, as opposed to whether it is reasonable.
A software smoke test determines whether the program launches and whether its interfaces are accessible and responsive (for example, the responsiveness of a web page or an input button). If the smoke test fails, it is impossible to conduct a sanity test. In contrast, the ideal sanity test exercises the smallest subset of application functions needed to determine whether the application logic is generally functional and correct (for example, an interest rate calculation for a financial application). If the sanity test fails, it is not reasonable to attempt more rigorous testing. Both sanity tests and smoke tests are ways to avoid wasting time and effort by quickly determining whether an application is too flawed to merit any rigorous testing. Many companies run sanity tests and unit tests on an automated build as part of their development process.

The Hello world program is often used as a sanity test for a development environment. If Hello World fails to compile or execute, the supporting environment likely has a configuration problem. If it works, the problem being diagnosed likely lies in the real application being diagnosed.