Final answer:
Mike should use the Start to Start (SS) dependency in a development project to allow testing to begin concurrently with the development of features, possibly with added lead time.
Step-by-step explanation:
If Mike wants the testing team to test completed features during the development of a project, he should use the Start to Start (SS) dependency. This type of dependency implies that the start of one task (in this case, testing) is dependent on the start of another task (in this case, feature development). Therefore, as soon as development on a feature begins, testing can also commence. However, to ensure testing of fully developed features, Mike may also need to incorporate a lead time into the schedule allowing the testing to start after a certain amount of development work has been completed.