> Were "passing tests" also generated by the same LLM?
No. The useful thing about porting a language runtime is that most of the tests are written in the language that it's a runtime for, not the implementation language. It's very easy to catch if the coding agent rewrites those tests.
I heard that Bun is not just a JS runtime, but much more than that. JavaScriptCore (JS engine Bun uses) is property tested outside of Bun anyways, what about other stuff?
No. The useful thing about porting a language runtime is that most of the tests are written in the language that it's a runtime for, not the implementation language. It's very easy to catch if the coding agent rewrites those tests.