The correct sequence in the causal chain is "Error, fault, failure". An error (or mistake) made by a person can lead to a fault (or defect) in the software. When the fault is executed, it may cause a failure in the software system. This sequence is important to understand the cause and effect relationship in software testing and defect management​​ .

Specification-based techniques, also known as black-box techniques, derive test cases from the specifications or requirements of the system. These techniques can be particularly useful when the test basis (such as documentation or requirements) is poorly defined or incomplete, as they provide a structured approach to testing based on the available specifications. This ensures that testing can proceed even when detailed documentation is lacking, helping to identify defects related to missing or incorrect functionality​​.

For a system with complex business rules and many branches, decision testing (a white-box technique) is appropriate because it ensures that each decision point (branch) in the code is tested. Equivalence partitioning (a black-box technique) complements this by ensuring that all functional areas (based on different inputs) are adequately tested. This combination provides thorough coverage of both the internal logic and the functional requirements of the system​​.

Static analysis tools are designed to analyze code without executing it. They are particularly good at finding defects related to code structure, such as variables that are not used or improperly declared. These tools can parse the code and identify issues that may not be easily detected through dynamic testing methods. Other issues like omission of a major requirement (A), inadequate decision coverage (B), and component memory leakage (C) are typically found through dynamic testing or higher-level verification techniques​​ .

Decision coverage is a testing metric used to ensure that all possible paths (decisions) in the code have been executed at least once. It is not used to verify the correctness of module calls, which is more related to integration testing or control flow testing. Options A, B, and D describe valid uses of decision coverage, ensuring that decisions are exercised in programs, business processes, and measuring the extent of coverage by a test suite​​ .

Test planning should be a continuous activity throughout the software development lifecycle. This ensures that the test plans remain relevant and effective, adapting to any changes in the project scope, requirements, or timelines.

Static analysis tools are used to detect certain types of defects without executing the code. According to the ISTQB CTFL syllabus v4.0, typical defects found by static analysis tools include variables that are never used, security vulnerabilities, and unreachable code. Poor performance and business processes not followed are not typically identified by static analysis tools​​.

Test execution tools include tools that directly assist in the execution of tests and comparison of actual outcomes with predicted outcomes. A test harness (b) is used to execute tests by providing the necessary context and data inputs for running a test. Test comparators (d) are used to compare the actual results produced by the system under test with the expected results, which is a key part of test execution.

For a web-based service designed to be available 24/7, a comprehensive testing approach is necessary to ensure functionality, security, reliability, and performance. Functional testing at the system level will verify the security aspects. Load testing at the system level will ensure the system can handle expected loads and remain available. Regression testing across all levels will confirm that changes do not introduce new defects. Structure-based testing at the component level will ensure the internal structure of components is robust. The ISTQB syllabus outlines these testing types and their importance in different contexts and levels​​.

Top of Form

Bottom of Form

Component testing, also known as unit testing, involves testing individual components of the software separately. This type of testing focuses on the functionality of a specific section of the code. To facilitate this process, stubs and drivers are often used. Stubs are dummy modules that simulate the behavior of lower-level modules that are not yet integrated. Drivers are used to simulate higher-level modules that control the component being tested.