Final answer:
A Test Fixture is the fixed state of a set of objects used as a baseline for running tests in software testing, ensuring a reproducible and known environment for test accuracy.
Step-by-step explanation:
A Test Fixture refers to option C, which is the fixed state of a set of objects used as a baseline for running tests in software testing. It is not just code to be executed before or after tests (options A and D), nor is it an annotation used in unit testing (option B). A Test Fixture ensures that there is a well-defined, known environment in which tests are run so that results are reproducible and can be compared to a known baseline.
In practice, this might involve setting up databases with specific data, initializing some objects to specific states, or configuring the system in a certain way before running tests. After the tests, the environment might be cleaned up or restored to ensure that subsequent tests can run in the same initial state. This pattern is critical for achieving test reliability and accuracy.