Lazy Systematic Unit TestingA J H Simons, JWalk: Lazy systematic unit testing of Java classes by design introspection and user interaction, ''Automated Software Engineering, 14 (4), December'', ed. B. Nuseibeh, (Boston: Springer, 2007), 369-418. is a software

unit test In computer programming, unit testing is a software testing method by which individual units of source code—sets of one or more computer program modules together with associated control data, usage procedures, and operating procedures&mda ...

ing method based on the two notions of ''lazy specification'', the ability to infer the evolving specification of a unit on-the-fly by dynamic analysis, and ''systematic testing'', the ability to explore and test the unit's state space exhaustively to bounded depths. A testing toolkit JWalk exists to support lazy systematic unit testing in the

Java programming language Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let programmers ''write once, run anywh ...

.''The JWalk Home Page'', http://www.dcs.shef.ac.uk/~ajhs/jwalk/

Lazy Specification

Lazy specification refers to a flexible approach to

software specification In computer science, formal specifications are mathematically based techniques whose purpose are to help with the implementation of systems and software. They are used to describe a system, to analyze its behavior, and to aid in its design by verif ...

, in which a specification evolves rapidly in parallel with frequently modified code. The specification is inferred by a semi-automatic analysis of a prototype software unit. This can include

static analysis Static analysis, static projection, or static scoring is a simplified analysis wherein the effect of an immediate change to a system is calculated without regard to the longer-term response of the system to that change. If the short-term effect i ...

(of the unit's interface) and

dynamic analysis Dynamic scoring is a forecasting technique for government revenues, expenditures, and budget deficits that incorporates predictions about the behavior of people and organizations based on changes in fiscal policy, usually tax rates. Dynamic scoring ...

(of the unit's behaviour). The dynamic analysis is usually supplemented by limited interaction with the programmer. The term Lazy specification is coined by analogy with ''

lazy evaluation In programming language theory, lazy evaluation, or call-by-need, is an evaluation strategy which delays the evaluation of an expression until its value is needed (non-strict evaluation) and which also avoids repeated evaluations (sharing). The b ...

'' in

functional programming In computer science, functional programming is a programming paradigm where programs are constructed by Function application, applying and Function composition (computer science), composing Function (computer science), functions. It is a declar ...

. The latter describes the delayed evaluation of sub-expressions, which are only evaluated on demand. The analogy is with the late stabilization of the specification, which evolves in parallel with the changing code, until this is deemed stable.

Systematic Testing

Systematic testing refers to a complete,

conformance testing Conformance testing — an element of conformity assessment, and also known as compliance testing, or type testing — is testing or other activities that determine whether a process, product, or service complies with the requirements of a specifi ...

approach to

software testing Software testing is the act of examining the artifacts and the behavior of the software under test by validation and verification. Software testing can also provide an objective, independent view of the software to allow the business to apprecia ...

, in which the tested unit is shown to conform exhaustively to a specification, up to the testing assumptions.A J H Simons, A theory of regression testing for behaviourally compatible object types, ''Software Testing, Verification and Reliability, 16 (3), UKTest 2005 Special Issue, September,'' eds. M Woodward, P McMinn, M Holcombe and R Hierons (Chichester: John Wiley, 2006), 133-156. This contrasts with exploratory, incomplete or random forms of testing. The aim is to provide repeatable guarantees of correctness after testing is finished. Examples of systematic testing methods include the Stream X-Machine testing methodF Ipate and W M L Holcombe, Specification and testing using generalised machines: a presentation and a case study, ''Software Testing, Verification and Reliability, 8 (2),'' (Chichester: John Wiley, 1998), 61-81. and equivalence partition testing with full

boundary value analysis Boundary-value analysis is a software testing technique in which tests are designed to include representatives of boundary values in a range. The idea comes from the boundary. Given that we have a set of test vectors to test the system, a topology ...

References

{{reflist Unit testing