Software testing takes place almost continuously throughout the software developmental life-cycle. Actually, module testing is the most detailed form of testing to be performed. The software programmer is generally responsible for testing the modules of the program, ensuring that each performs the function for which it was designed. Therefore, managers should know how to allocate the specified testing-resources among all the modules and develop quality software with high reliability. We present the optimal policies of testing-resource allocation for modular software systems. Our methodologies provide practical approaches to the optimization of testing-resource allocation with a reliability objective. Some theorems and numerical examples for the optimal testing-effort allocation policies are demonstrated. Besides, sensitivity analysis is also discussed in detail. Using the proposed strategies for module testing, project managers can make the best decisions.