🤖 AI Summary
为确保MongoDB在多种编程语言中的客户端库行为一致，开发了基于YAML的统一测试格式，减少了非一致性错误。
📝 Abstract
MongoDB maintains client libraries in a dozen programming languages, used by tens of thousands of organizations and millions of developers. Most are implemented natively rather than as wrappers around a shared core. Ensuring consistent behavior across these libraries, comprising millions of lines of code, is hard but essential. Over eleven years, we developed a specification-based testing approach: tests are written once in YAML and executed by language-specific interpreters for each library. We describe the evolution from many ad-hoc formats to a Unified Test Format, which allowed us to delete over 22,000 lines of test code. The rate of nonconformance bugs fell up to 86% in drivers that adopted YAML tests (though results varied). We report lessons learned about declarative test design, test architecture, schema evolution, and the limits of unification.