רון שטרן

Continuous Integration (CI) builds execute large test suites that often yield multiple simultaneous failures, many originating from a common underlying fault. Test failure triage - grouping failing tests by their root cause - is therefore critical for reducing debugging effort. Existing approaches work poorly in CI builds with multiple faults, and either lack semantic reasoning or ignore highly informative structural and change-aware signals. To address these limitations, we propose HyTri, a framework that integrates LLM-guided causal reasoning into test failure triage. HyTri derives similarity signals that consider failure semantics and hypothesized root causes. It fuses these signals using confidence weighting and error-type adjustment into a unified similarity measure that is used to cluster the failing tests. To evaluate HyTri we created Multi-Fault CI Builds Benchmark (MFCI-Benchmark), a novel benchmark for test failure triage algorithms comprising synthesized multi-fault CI builds from well-known bug repositories. Experimental results over MFCI-Benchmark and the multifault Defects4J fault localization benchmark showed that HyTri outperforms existing baselines, maintaining strong performance even in datasets where stack traces are shallow and uninformative.