Label-free code model tuning with self-generated tests
A code-generation training loop that co-evolves tests with solutions is now concrete enough to try in internal fine-tuning and eval pipelines. ZeroCoder shows that execution feedback from self-generated code and self-generated tests can improve both sides without human-written tests or reference solutions. On Qwen2.5-Coder-7B-Instruct, the label-free setup improved code generation by 14.5%, and DyB^4 raised that to 21.6%; across three model families and six benchmarks, average gains reached 18.8% for code generation and 62.7% for test generation. The practical build is a small runner that samples multiple candidate programs and tests for each task, executes the full pass/fail matrix, drops low-information tasks, and tracks whether discriminative tests improve mutation scores before they are trusted as rewards. This fits teams that already have code tasks but do not have large stores of curated unit tests. A cheap check is to run it on one narrow internal task family and compare Pass@1 and mutation score against a standard execution-only baseline.