We maintain a lightweight platform alongside a legacy platform that is an untestable ball of mud. This resulted from rapid implementation of business demands ov

We maintain a lightweight platform alongside a legacy platform that is an untestable ball of mud. This resulted from rapid implementation of business demands over the years, along with a practice of addressing numerous data quality problem through hacks in components, rather than cleaning the data or using a sanitization layer to access it. Lack of dependency inversion in systems like this is truly the road to ruin, as the system complexity grows so quickly in time, due to interactions, that eventually nobody really understands what it does or why it does it. I suppose this is tolerable for some applications, but if you need to numerically validate it, it's a nightmare.