11. The computer-implemented method of claim 10 wherein the software DUT model also comprises unknown models that generate model outputs in an unknown state; wherein the unknown models are for blocks in the target device that have not yet been modeled or have not yet been designed; wherein the fuzzy models are for blocks in the target device that have already been modeled or designed; wherein the unknown models generate model outputs in an unknown state; wherein model inputs to fuzzy models are previously-stored state signals, test inputs from test vectors, model outputs from other fuzzy models, or model outputs from unknown models.
10. A computer-implemented method for generating a self-check test program comprising: selecting a selected instruction from a plurality of instructions in an instruction set for executing on a target device that is an intended device-under-test (DUT); determining when necessary blocks in the target device are available as fuzzy models in a software DUT model that emulates operation of the target device; skipping and not executing the selected instruction on the software DUT model and not adding the selected instruction to the self-check test program when the necessary blocks are determined to be unavailable as fuzzy models in the software DUT model; when the necessary blocks are determined to be available as fuzzy models in the software DUT model, determining when a known state is required for the selected instruction; skipping and not executing the selected instruction on the software DUT model and not adding the selected instruction to the self-check test program when the known state is required but not available on the software DUT model; executing the selected instruction on the software DUT model to generate an updated state and adding the selected instruction to the self-check test program when the known state is required and available on the software DUT model or when the known state is not required; and continuing to select and process other instructions from the plurality of instructions in the instruction set as the selected instruction to generate the self-check test program, whereby the self-check test program is generated by selecting instructions that have fuzzy models available on the software DUT model.