A system and method for detecting and/or preventing execution problems caused by user-supplied code modules that are called by steps of a test executive sequence. The test executive sequence may include a plurality of test executive steps. At least a subset of the steps may be configured to call user-supplied code modules. The test executive sequence may be executed on a host computer under control of a test executive engine. For each step that calls a user-supplied code module, the test executive engine may perform certain actions to detect and/or prevent execution problems caused by the user-supplied code module. For example, the test executive engine may be operable to automatically detect stack corruption caused by the user-supplied code module, may be operable to utilize stack safety buffers to avoid stack corruption problems caused by the user-supplied code module, and/or may include features for aiding a user in determining whether the user-supplied code module contains an uninitialized local variable.