While conducting a unit test, a developer would use a

During unit testing, a developer often uses a driver or stub to isolate the unit being tested. A driver simulates a higher-level module that calls the unit under test, while a stub simulates a lower-level module or service called by the unit. These test aids allow the developer to test a module before all related modules are completed or integrated. Black-box test cases can be used at different levels, but they do not specifically describe the support tools commonly used during unit testing. Top-down and bottom-up describe integration strategies, not unit test aids. Scenario-based test cases are often used for user or system-level behavior. Therefore, driver or stub is the best answer.

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