Electronic instrumentation used in conjunction with germanium gamma‐ray detectors for astrophysics observations must be tested under conditions similar to those encountered during actual operations. Simulation of cosmic‐rays, gamma‐ray bursts and solar flares is necessary to validate the performance of the entire spectroscopy chain. A random charge pulser used in conjunction with other diagnostic pulsers, and the techniques developed to verify the performance with and without a germanium gamma‐ray detector are described.