RM -RF: Reward Model for Run-Free Unit Test Evaluation
This work proposes the first lightweight reward model capable of predicting multidimensional test quality—including executability, code coverage, and mutation kill rate—without executing tests, thereby circumventing the high latency and resource overhead inherent in traditional unit test evaluation that relies on repeated compilation and execution. Leveraging a multilingual dataset constructed from Java, Python, and Go, the model is trained using parameter-efficient strategies such as zero-shot inference, full fine-tuning, and LoRA. It achieves an average F1 score of 0.69 across all three quality metrics. By eliminating the need for actual test runs, this approach substantially reduces evaluation cost and latency, offering an efficient foundation for large-scale test generation and reinforcement learning–based test optimization.