Automated Unit Test Generation for NestJS APIs Using AST, OpenAPI, and Few-Shot Prompting

This paper presents a pipeline that combines AST parsing, OpenAPI specifications, and few-shot prompting to automatically generate unit tests for NestJS RESTful APIs. Evaluated on 18 endpoints with Llama-3.3-70B, it reached a 75% test pass rate and 94.17% BERTScore F1 at about 2.5 seconds per endpoint.