1. A carrier medium comprising program instructions executable to: include a plurality of test executive steps in a test executive sequence in response to user input; configure each of the test executive steps to call a user-supplied code module in response to user input; and execute the test executive sequence, wherein said executing comprises executing each of the test executive steps in the test executive sequence; wherein for each test executive step in the test executive sequence, said executing the test executive step comprises: storing a first portion of a stack; invoking execution of the user-supplied code module called by the test executive step; and checking the stored portion of the stack against contents of the stack after the user-supplied code module called by the test executive step finishes executing to determine whether any contents in the first portion of the stack changed during execution of the user-supplied code module called by the test executive step.