Which of the following describes a test case?

The concept of a test case is best captured by the description that outlines it as a set of conditions or variables under which a tester assesses whether a system or software application is functioning correctly. A test case provides detailed information about the inputs, execution conditions, and the expected results.

Such a structure allows testers to evaluate a specific functionality of the software by defining what is to be tested, how it will be tested, and what the expected outcome should be if the software meets the requirements. This structured approach is critical because it ensures that each aspect of the software is validated against its requirements, aiding in the detection of defects or issues.

Other descriptions, while related to the testing process, do not accurately define what a test case specifically is. For instance, a document outlining testing objectives and expected outcomes pertains more to a test plan rather than an individual test case. Similarly, a listing of defects emphasizes the outcomes of testing but is not concerned with the actual conditions set for executing a test case. Lastly, measuring software performance refers to performance testing rather than the specifics of defining and conducting a test case.