Which of the following principles apply to testing? (Choose two.)

This question assesses knowledge of the seven fundamental principles of software testing.

A. In general, exhaustive testing is not possible: This is Principle 2. Testing all possible combinations of inputs, preconditions, and execution paths is infeasible for any non-trivial software. Testers must use risk analysis and prioritization to focus efforts.

B. Where many errors exist, more errors are usually hidden: This is a direct consequence of Principle 4, "Defects cluster together." This principle observes that a small number of modules or components usually contain most of the defects, so finding several defects in one area makes it a good place to look for more.

C. This contradicts Principle 1, "Testing shows the presence of defects, not their absence." Testing can reveal that defects exist but cannot prove that no defects remain.

D. This is Principle 7, the "Absence-of-errors fallacy." Finding and fixing defects does not guarantee the system is useful or meets user needs if the requirements were incorrect.

1. International Software Testing Qualifications Board (ISTQB®). (2018). Certified Tester Foundation Level Syllabus Version 2018. Section 1.3

"Seven Testing Principles (K2)"

pp. 8-9.

Page 8

Principle 2: "Exhaustive testing is impossible. Testing everything (all combinations of inputs and preconditions) is not feasible except for trivial cases." (Supports answer A).

Page 9

Principle 4: "Defects cluster together. A small number of modules or components usually contains most of the defects discovered during pre-release testing

or is responsible for most of the operational failures." (Supports answer B).

Page 8

Principle 1: "Testing shows the presence of defects

not their absence. Testing can show that defects are present

but cannot prove that there are no defects." (Refutes option C).

Page 9

Principle 7: "Absence-of-errors fallacy. Some organizations expect that testers can run all possible tests and find all possible defects

but Principles 2 and 1

respectively

tell us that this is impossible. Further

it is a fallacy to expect that just finding and fixing a large number of defects will ensure the success of a system. For example

thoroughly testing all the specified requirements and fixing all the defects found could still produce a system that is difficult to use

that does not fulfill the users’ needs and expectations..." (Refutes option D).