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150 A. L.Smith increases. This might be because you are just starting to apply format test design techniques,or it mightbebecauseyouare focusing toomuchonone technique. Mutation testing information can help you prioritize resources to maximize test coverageinnewways. 3 CodeCoverage and Mutation Operators On the one hand, mutation testing is a black-box testing technique, as the design and execution of the tests do not require knowledge of the inner workings of the code. That said, the mutation operators and the fault injection process must have very detailed knowledge of the code, or at least, a mutable derivation of it. In fact, the set of mutants generated is inextricably linked to the language and structure of theunderlyingcode,but thenagainsoare real faults. When themutation“operator”injects faults into thecode, it performsrule-based changes, which can usually be customized by the engineers working on the code. Someexampleof these include: • Deletingstatements fromthe code • Insertingstatements fromcode • Alteringconditions incode • Replacingvariablevalues Let’s go over some basic programmingconcepts, and how they link to faults, code coverage and mutation testing. In most programming languages, an executable statementexpressesanactiontobecarriedout,suchasassigningavalue,e.g. trueor false, to a variable. The ISTQB glossary defines this as: “A statement which, when compiled, is translated into object code, and which will be executed procedurally when the programis runningandmayperformanactionondata.” For example, in the code below, the statements all of the lines that don’t start IF/ELSEarestatements: Pseudo Code allowEntrance = false if (customerHasMembershipCard or customerHasAccessCard): allowEntrance = true price = 0 else: if(weekend): allowEntrance = true price = 10