ISTQB Updated ISTQB-CTFL Exam Questions and Answers by asiyah

Component testing (also known as unit testing or module testing) is a level of testing that focuses on verifying the functionality and quality of individual software components (such as modules, classes, functions, methods, etc.). Component testing mainly tests interfaces and interaction between components, as well as internal logic and data structures of the components. Component testing may be applied using a test-first approach (such as test-driven development or behavior-driven development), where tests are written before the code is implemented. Component testing does not identify defects in modules and classes, as this is a result of component testing, not an objective. Simulators and stubs may be required for component testing, as they can simulate or replace missing or incomplete components or external systems that are needed for testing. Verified References: A Study Guide to the ISTQB® Foundation Level 2018 Syllabus - Springer, page 19.

Covering all transitions at least once is the highest coverage criterion for state transition based test cases, because it ensures that every possible change of state is tested at least once. This means that all the events that trigger the transitions, as well as the actions and outputs that result from the transitions, are verified. Covering all transitions at least once also implies covering all states at least once, but not vice versa. Therefore, option D is not the highest coverage criterion. Option C is the lowest coverage criterion, because it only tests the initial and final states of the system or component, without checking the intermediate states or transitions. Option A is incorrect, because the coverage criteria for state transition based test cases can be determined and compared based on the number of transitions and states covered. References = CTFL 4.0 Syllabus, Section 4.2.3, page 49-50.