I recently spent some spare time reworking cluacov , a C extension around LuaCov , with help from GPT-5.5 and Claude Opus 4.7. The result was a branch-coverage pipeline with real output: https://shansan.top/cluacov/ . The test corpus behind that report lives in the e2e directory . 【中文】 Introduction Line coverage answers a simple question: "Did this line execute?" That is useful, but it is often not the question you actually care about. For testing quality, the stronger question is: "Did both paths of this branch execute?" Consider this Lua code: if a or b or c then do_something () end Enter fullscreen mode Exit fullscreen mode A line-based tool can only tell you that the if line ran. It cannot tell you whether only a was tested, or whether b and c were also reached. At the bytecode level, the Lua compiler emits three independent TEST decisions for the short-circuit chain. That means there are three distinct branch sites, not one.…