Training configuration
Stage 1: offline policy distillation
Table with columns: Setting, Value| Setting | Value |
|---|
| Student | Qwen/Qwen3-8B |
| Teacher | Qwen/Qwen3-14B |
| Objective | forward KL over teacher top-k logits |
| Teacher top-k | 256 |
| Policy-gradient term | disabled |
| Precision | BF16 |
| Learning rate | 3e-6, constant schedule |
| Epochs | 1 |
| Global batch size | 32 |
| Per-GPU micro batch | 1 |
| Gradient accumulation | 32 |
| Rollout samples | 1 |
| Temperature | 1.0 |
| Maximum prompt/response length | 4096 / 4096 tokens |
| Seed | 42 |
Stage 2: mutation-aware GRPO
Table with columns: Setting, Value| Setting | Value |
|---|
| Starting policy | OPD model from stage 1 |
| Training examples | 1,582 mutation-applicable Defects4J training samples |
| Algorithm | GRPO, no KL term in reward |
| Configured epochs | 2 |
| Learning rate | 1e-6 |
| Global prompt batch | 32 |
| Rollouts per prompt | 8 |
| PPO prompt groups / expanded mini batch | 4 / 32 |
The reward is -1 for an invalid generated test. A valid test receives
0.4 * line_coverage + 0.6 * branch_coverage + mutation_score. Mutation
analysis samples up to three eligible failing mutants per rollout, with a
mutation weight of 1.0. Coverage credit is gated by focal-call, assertion, and
local focal-data provenance checks.
Intended use
The model is intended for research on Java unit-test generation and
reinforcement learning for software engineering. Generated tests must be
compiled and executed in an isolated environment before use.