Challenges in Testing Large Language Model-Based Software: A Faceted Taxonomy

Felix Dobslaw, ROBERT H. FELDT, Juyeon Yoon, Shin Yoo

ACM Transactions on Software Engineering and Methodology 2026 article cited by 4

importance 6/10 partially solved Software Testing and Debugging Techniques software testing stage: research

LLM-based software is non-deterministic, so traditional testing cannot verify correctness within individual test cases.

LLMs are becoming integral to software systems, making undetected output variability a correctness risk.

Provides a four-faceted taxonomy of LLM test case design, an LLM-assisted analysis of six open-source testing frameworks, and a sensitivity study of an agent-based system across model configurations.

Taxonomy with four facets; analysis of six open-source testing frameworks; sensitivity study across model configurations

Organizes the field and identifies open challenges; does not solve LLM software testing.

Venue ACM Transactions on Software Engineering and Methodology
Published 2026
Work type article
Authors Felix Dobslaw, ROBERT H. FELDT, Juyeon Yoon, Shin Yoo
Citations 4 (OpenAlex, at import time)
References 16
Model or method not stated in source
Organization not stated in source
Primary source https://doi.org/10.1145/3806396
Open access hybrid
Keywords LLM testing, non-determinism, test case design, taxonomy, multi-agent LLMs
6 / 10

significant — thousands to millions affected

Correctness verification for LLM-based software is a foundational challenge as LLMs become integral to software systems; abstract frames it as a field-wide open problem but gives no scale.

Basis: inferred. Judged from the source text, which gives no explicit scale. Stated scale: not stated in source. Method and limits.

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