In this paper, based on software reliability growth models with generalized logistic testing-effort function, we study three optimal resource allocation problems in modular software systems during testing phase: 1) minimization of the remaining faults when a fixed amount of testing-effort and a desired reliability objective are given, 2) minimization of the required amount of testing-effort when a specific number of remaining faults and a desired reliability objective are given, and 3) minimization of the cost when the number of remaining faults and a desired reliability are given. Several useful optimization algorithms based on the Lagrange multiplier method are proposed and numerical examples are illustrated. Our methodologies provide practical approaches to the optimization of testing resource allocation with a reliability objective. In addition, we also introduce the testing-resource control problem and compare different resource allocation methods. Finally, we demonstrate how these analytical approaches can be employed in the integration testing. Using the proposed algorithms, project managers can allocate limited testing resource easily and efficiently and thus achieve the highest reliability objective during software module and integration testing.