Which of the following is an advantage in using a bottom-up versus a top-down approach to software testing?
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A. B. C. D.B.
The bottom-up approach to software testing begins with the testing of atomic units, such as programs and modules, and work upwards until a complete system testing has taken place.
The advantages of using a bottom-up approach to software testing are the fact that there is no need for stubs or drivers and errors in critical modules are found earlier.
The other choices refer to advantages of a top down approach which follows the opposite path.
Source: Information Systems Audit and Control Association, Certified Information Systems Auditor 2002 review manual, chapter 6: Business Application System Development, Acquisition, Implementation and Maintenance (page 299).
In software testing, the two most commonly used approaches are top-down and bottom-up. Top-down testing starts with the highest-level modules and works down to the lowest level, while bottom-up testing begins with the lowest-level modules and works its way up to the highest level.
Advantages of bottom-up testing versus top-down testing:
A. Interface errors are detected earlier: In bottom-up testing, lower-level modules are tested before higher-level modules, which means that any interface errors between modules will be detected earlier. This is because lower-level modules are tested in isolation, which helps identify interface issues before they become embedded in higher-level modules.
B. Errors in critical modules are detected earlier: Critical modules, which are the most important parts of the system, are tested earlier in the bottom-up approach because they are the ones that the rest of the system relies on. If there are errors in these modules, they will be detected earlier in the bottom-up approach because they are tested first.
C. Confidence in the system is achieved earlier: With the bottom-up approach, because testing is done on individual modules, and the modules are combined gradually, testing can begin early and increase the confidence of developers that the overall system is functioning as intended. This means that confidence in the system can be achieved earlier, which can be useful for developers who need to know that the system is functioning properly.
D. Major functions and processing are tested earlier: The major functions and processing are tested earlier in the bottom-up approach because they are usually present in the lowest-level modules. Since the lower-level modules are tested first, any major function or processing errors will be detected earlier in the testing process.
Overall, the bottom-up approach provides an advantage over the top-down approach because it focuses on testing the system's critical components and interfaces first, allowing developers to identify and fix errors earlier in the development cycle.