That's a really good example of the problems of indirection. I'll use it in future if that's ok. The thing that drives me mad about the promoters of decoupling

That's a really good example of the problems of indirection. I'll use it in future if that's ok. The thing that drives me mad about the promoters of decoupling is that they rarely talk about the downsides. The truth is that every time you decouple something there is a cost in complexity. One individual step to decouple something may seem small but the cumulative effect of many indirections in code can make it extremely difficult to navigate and understand. So when people decouple something they should understand this and make sure that the benefit outweighs the cost (which of course it does in some cases). The benefit of being able to test your code at a micro level rarely outweighs the cost.