Unit and integration testing are two expected levels of testing for conventionally designed programs. This article presents a system for the automatic generation of test plans for incremental unit and integration testing. Starting from a global task of planning integration testing, the system generates a detailed test plan automatically for a given program on the basis of its decomposition as a software structure. The system is implemented as a frame‐based system. It supports four standard ways of assembling units during integration, and two ways of testing according to parallelism. It also takes into account the units that require more testing than others. The system greatly improves the productivity of planning integration testing in comparison with the current practice of producing test plans manually. Experiments have shown a minimum productivity increase of 55 times. © 1998 John Wiley & Sons, Ltd.