What is a "test case" in QA?

A "test case" in Quality Assurance is fundamentally defined as a set of conditions for testing software functionality. It serves as a detailed scenario that outlines exactly how a particular functionality of the application should be tested to ensure it meets the specified requirements. Each test case typically includes various components such as the test case ID, description, preconditions, input data, expected results, and postconditions. This structured format allows testers to systematically validate whether the software performs as expected under varying conditions.

In essence, test cases are essential because they provide a clear and repeatable method for testing software, facilitating comprehensive coverage of functional and non-functional aspects. This structured approach ensures that developers address any inconsistencies or bugs, ultimately leading to a more reliable and high-quality product. The other options do not accurately describe a test case; for instance, a report of defects pertains to issues discovered, not the test process itself, while installation guides and UI design documents relate to implementations and designs rather than testing.