Yes, I figure it would have been easy to get to 100% if MySQL had been designed so that plugins could be coverage tested. For example, there might be an "envir

Yes, I figure it would have been easy to get to 100% if MySQL had been designed so that plugins could be coverage tested. For example, there might be an "environment" API which abstracts memory management and file I/O. The plugin could use this API instead of direct calls. Then if MySQL had an option to use a specific environment implementation for a plugin, then testers could drop in their own implementation under test. Getting that sort of support by MySQL is an example of what I think you mean by "cultural challenge."