Final answer:
The claim that all test cases must be pre-planned during execution-based testing is false, especially in agile environments where tests can be ad-hoc and exploratory. While structured tests have benefits, preserving test cases after execution is useful for regression testing and future reference.
Step-by-step explanation:
The statement that during execution-based testing, all test cases must be planned beforehand, including the expected output, and retained afterwards is false. In many software development life cycles, particularly those following agile or iterative methodologies, test cases evolve as the project progresses. Testing can be exploratory in nature, whereby testers design and execute tests on-the-fly based on their domain knowledge and software behavior during execution.
This approach contrasts planning out all test cases in advance; it relies on the tester's skill and experience, as well as a deep understanding of the software's intended functionality. However, having structured test cases in place is advantageous when the situation allows for thorough planning. This can provide a baseline for certain aspects of testing and help in tracking bugs and other issues systematically.
Nevertheless, retaining test cases after they have been executed can be beneficial for future reference and regression testing, irrespective of how they were initially planned. Test execution results and artifact retention help in maintaining a strong test documentation that can guide future testing efforts and aid in understanding the software development history.