Tests are becoming the control surface for code generation
Work on coding systems centers on executable checks as the training signal. ZeroCoder improves a code model without reference solutions or human tests by co-evolving code and test generation, then scoring both through execution. On Qwen2.5-Coder-7B-Instruct, the fully label-free setup improves code generation by 14.5%, and DyB4 raises that gain to 21.6%; across three model families and six benchmarks, average gains reach 18.8% for code generation and 62.7% for test generation. A smaller paper on Test-Oriented Programming pushes the same idea into workflow design: developers review generated tests, then let the model write production code. Its Onion prototype completed a small BibTeX CLI task in all 10 runs, with no direct production-code edits, though the evidence stays narrow because the evaluation is a single small application.