What type of defect is a test harness most likely to detect?

A test harness is primarily designed to provide a controlled environment in which automated tests can be executed. This setup is particularly effective for identifying defects in components that interact with different parts of the system, especially middleware, which facilitates communication and data management between software applications.

Middleware defects might include issues related to data formats, message passing errors, or communication failures between applications. Since a test harness typically simulates various conditions and interactions in a manageable way, it can effectively identify these kinds of defects during integration and system testing phases.

In this context, the ability of the test harness to verify the correct functioning of the middleware and validate its integration with other software components makes it a vital tool in detecting such defects.