I'm not sure what you're finding harmful when it sounds to me like you're agreeing. Your "library code" (or library-esq elements) is the code that you find need

I'm not sure what you're finding harmful when it sounds to me like you're agreeing. Your "library code" (or library-esq elements) is the code that you find needs to be tested more heavily, because it is library code? I don't thing whether it's packaged separately was key to that, but it can help.