An identical request to process a transaction is initiated at a trusted subsystem of a system and a new subsystem of the system. Computed indicia of the transaction from both subsystems are compared at the trusted subsystem. An error condition is generated that indicates a logic error in the new subsystem when the comparison indicates that the computed indicia of the new subsystem does not match the computed indicia of the trusted subsystem. The error condition indicates a lack of transactional integrity in the new subsystem. The new subsystem may be taken out of service after the error condition is generated.