DuET: Dual Execution for Test Output Prediction with Generated Code and Pseudocode

Hojae Han, Jaejin Kim, Seung-won Hwang, Yu Jin Kim, Moontae Lee


Abstract
This work addresses test output prediction, a key challenge in test case generation. To improve the reliability of predicted outputs by LLMs, prior approaches generate code first to ground predictions. One grounding strategy is direct execution of generated code, but even minor errors can cause failures. To address this, we introduce LLM-based pseudocode execution, which grounds prediction on more error-resilient pseudocode and simulates execution via LLM reasoning. We further propose DUET, a dual-execution framework that combines both approaches by functional majority voting. Our analysis shows the two approaches are complementary in overcoming the limitations of direct execution suffering from code errors, and pseudocode reasoning from hallucination. On LiveCodeBench, DUET achieves the state-of-the-art performance, improving Pass@1 by 13.6 pp. For filtering candidates in code generation, DUET shows the best Pass@1 on LiveCodeBenchEasy, BigCodeBench-Hard, DevEval and HumanEval(+).
Anthology ID:
2026.findings-acl.2144
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
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Findings
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Publisher:
Association for Computational Linguistics
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Pages:
43221–43243
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.2144/
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Cite (ACL):
Hojae Han, Jaejin Kim, Seung-won Hwang, Yu Jin Kim, and Moontae Lee. 2026. DuET: Dual Execution for Test Output Prediction with Generated Code and Pseudocode. In Findings of the Association for Computational Linguistics: ACL 2026, pages 43221–43243, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
DuET: Dual Execution for Test Output Prediction with Generated Code and Pseudocode (Han et al., Findings 2026)
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