Abstract: A method for verifying the architectural integrity of a newly written or modified instruction set in a limited operating environment is described. More particularly, this methodology is adapted to perform such verification even though the processor under test has only a one or a few instructions in its partially complete instruction set. Such verification is accomplished using a minimum test driver, under control of a test processor, which loads the data necessary to execute the instruction being tested. The test system also provides actual or simulated I/O capabilities. After execution of that instruction, the test driver directs capture of the execution results for appropriate use. As an aid in performing the verification test, the test driver is provided with an invalid command that forces return of control to the test processor.