Overview

Coverage-Directed Test Selection is a technique for simulation-based hardware verification. It was introduced to address a common limitation of constrained random test generation: while randomness provides diversity, tests often repeatedly exercise the same design logic, and as verification progresses many tests contribute little or nothing to functional coverage.[1][2]

Core idea

The technique is most applicable when generating stimuli is much cheaper than simulating them. In that setting, the proposed strategy is to generate a large number of tests, select the most effective subset, and simulate only that subset.[3]

The method is described as automatic constraint extraction and test selection based on supervised learning from coverage feedback.[4] It biases selection toward tests that have a high probability of increasing functional coverage and prioritizes those tests for simulation.[5]

Reported benefits

The introducing paper reports that Coverage-Directed Test Selection can reduce manual constraint writing, prioritize effective tests, reduce verification resource consumption, and accelerate coverage closure. The reported evaluation was performed on a large, real-life industrial hardware design.[6]

Relationship to Hybrid Intelligent Testing

Coverage-Directed Test Selection is also used as a component of Hybrid Intelligent Testing in Simulation-Based Verification. In that hybrid approach, it is combined with Novelty-Driven Verification; the abstract describes Coverage-Directed Test Selection as learning from coverage feedback to bias testing toward the most effective tests.[7]

References

[1]–[6] Supervised Learning for Coverage-Directed Test Selection in Simulation-Based Verification. [7] Hybrid Intelligent Testing in Simulation-Based Verification.