A method of verifying integrated circuit designs, by constructing a series of atomic generators in a staged, hierarchical order, applying a lowest of the hierarchical generator stages to device level test cases of the verification process, applying a highest of the hierarchical generator stages to system level test cases of the verification process, reusing code written for and used in the lowest hierarchical generator stage in a next higher generator stage, creating a constraint scenario in the highest hierarchical generator stage, and injecting the constraint scenario into a next lower generator stage.