Software verification

Software verification is a broad and complex discipline of software engineering whose goal is to assure that software fully satisfies all the expected requirements.

There are two fundamental approaches to verification:
* "Dynamic verification", also known as Test or Experimentation
* "Static verification", also known as Analysis

Dynamic verification (Test,Experimentation)

Dynamic verification is performed during the execution of software, and dynamically checks its behaviour; it is commonly known as the Test phase.Verification is a Review Process.Depending on the scope of tests, we can categorize them in three families:
* "Test in the small": a test that checks a single function or class (Unit test)
* "Test in the large": a test that checks a group of classes, such as
** Module test (a single module)
** Integration test (more than one module)
** System test (the entire system)
* "Acceptance test": a formal test defined to check acceptance criteria for a software
** Functional test
** Non functional test (performance, stress test)

Software verification is often confused with software validation. The difference between verification" and validation"':
* Software "verification" asks the question, "Are we building the product right?"; that is, does the software conform to its specification.
* Software "validation" asks the question, "Are we building the right product?"; that is, is the software doing what the user really requires.The aim of software verification is to find the errors introduced by an activity, i.e. check if the product of the activity is as correct as it was at the beginning of the activity.

The aim of software validation is to declare whether the product of an activity is indeed what is expected, i.e. the activity extended the product successfully.

Static verification (Analysis)

Static verification is the process of checking that software meets requirements by doing a physical inspection of it. For example:
* "Code conventions verification"
* "Bad practices detection"
* Software metrics calculation
* Formal verification

References

* IEEE: "SWEBOK: Guide to the Software Engineering Body of Knowledge"
* Carlo Ghezzi, Mehdi Jazayeri, Dino Mandrioli: "Fundamentals of Software Engineering", Prentice Hall, ISBN 0-13-099183-X